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Using the GNU Privacy Guard
***************************

This is the `The GNU Privacy Guard Manual' (version 2.0.22,
October 2013).

Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 3 of the
License, or (at your option) any later version. The text of the
license can be found in the section entitled "Copying".

This manual documents how to use the GNU Privacy Guard system as
well as the administration and the architecture.

* Menu:

* Installation:: A short installation guide.

* Invoking GPG-AGENT:: How to launch the secret key daemon.
* Invoking GPG:: Using the OpenPGP protocol.
* Invoking GPGSM:: Using the S/MIME protocol.
* Invoking SCDAEMON:: How to handle Smartcards.
* Specify a User ID:: How to Specify a User Id.

* Helper Tools:: Description of small helper tools

* Howtos:: How to do certain things.
* System Notes:: Notes pertaining to certain OSes.
* Debugging:: How to solve problems

* Copying:: GNU General Public License says
how you can copy and share GnuPG
* Contributors:: People who have contributed to GnuPG.

* Glossary:: Short description of terms used.
* Option Index:: Index to command line options.
* Index:: Index of concepts and symbol names.

File: gnupg.info, Node: Installation, Next: Invoking GPG-AGENT, Prev: Top, Up: Top

1 A short installation guide.
*****************************

Unfortunately the installation guide has not been finished in time.
Instead of delaying the release of GnuPG 2.0 even further, I decided to
release without that guide. The chapter on gpg-agent and gpgsm do
include brief information on how to set up the whole thing. Please
watch the GnuPG website for updates of the documentation. In the
meantime you may search the GnuPG mailing list archives or ask on the
gnupg-users mailing listsfor advise on how to solve problems or how to
get that whole thing up and running.

** Building the software

Building the software is decribed in the file `INSTALL'. Given that
you are already reading this documentation we can only give some extra
hints

To comply with the rules on GNU systems you should have build time
configured `dirmngr' using:

./configure --sysconfdir=/etc --localstatedir=/var

This is to make sure that system wide configuration files are
searched in the directory `/etc/gnupg' and variable data below `/var';
the default would be to also install them below `/usr/local' where the
binaries get installed. If you selected to use the `--prefix=/' you
obviously don't need those option as they are the default then.

** Explain how to setup a root CA key as trusted

Such questions may also help to write a proper installation guide.

[to be written]

XXX Tell how to setup the system, install certificates, how dirmngr
relates to GnuPG etc.

** Explain how to setup a root CA key as trusted

X.509 is based on a hierarchical key infrastructure. At the root of
the tree a trusted anchor (root certificate) is required. There are
usually no other means of verifying whether this root certificate is
trustworthy than looking it up in a list. GnuPG uses a file
(`trustlist.txt') to keep track of all root certificates it knows
about. There are 3 ways to get certificates into this list:

* Use the list which comes with GnuPG. However this list only
contains a few root certificates. Most installations will need
more.

* Let `gpgsm' ask you whether you want to insert a new root
certificate. To enable this feature you need to set the option
`allow-mark-trusted' into `gpg-agent.conf'. In general it is not
a good idea to do it this way. Checking whether a root
certificate is really trustworthy requires decisions, which casual
users are not up to. Thus, by default this option is not enabled.

* Manually maintain the list of trusted root certificates. For a
multi user installation this can be done once for all users on a
machine. Specific changes on a per-user base are also possible.

XXX decribe how to maintain trustlist.txt and
/etc/gnupg/trustlist.txt.

** How to get the ssh support running

XXX How to use the ssh support.

1.1 Installation Overview
=========================

XXXX

File: gnupg.info, Node: Invoking GPG-AGENT, Next: Invoking GPG, Prev: Installation, Up: Top

2 Invoking GPG-AGENT
********************

`gpg-agent' is a daemon to manage secret (private) keys independently
from any protocol. It is used as a backend for `gpg' and `gpgsm' as
well as for a couple of other utilities.

The usual way to run the agent is from the `~/.xsession' file:

eval $(gpg-agent --daemon)
If you don't use an X server, you can also put this into your regular
startup file `~/.profile' or `.bash_profile'. It is best not to run
multiple instance of the `gpg-agent', so you should make sure that only
one is running: `gpg-agent' uses an environment variable to inform
clients about the communication parameters. You can write the content
of this environment variable to a file so that you can test for a
running agent. Here is an example using Bourne shell syntax:

gpg-agent --daemon --enable-ssh-support \
--write-env-file "${HOME}/.gpg-agent-info"

This code should only be run once per user session to initially fire
up the agent. In the example the optional support for the included
Secure Shell agent is enabled and the information about the agent is
written to a file in the HOME directory. Note that by running
gpg-agent without arguments you may test whether an agent is already
running; however such a test may lead to a race condition, thus it is
not suggested.

The second script needs to be run for each interactive session:

if [ -f "${HOME}/.gpg-agent-info" ]; then
. "${HOME}/.gpg-agent-info"
export GPG_AGENT_INFO
export SSH_AUTH_SOCK
fi

It reads the data out of the file and exports the variables. If you
don't use Secure Shell, you don't need the last two export statements.

You should always add the following lines to your `.bashrc' or whatever
initialization file is used for all shell invocations:

GPG_TTY=$(tty)
export GPG_TTY

It is important that this environment variable always reflects the
output of the `tty' command. For W32 systems this option is not
required.

Please make sure that a proper pinentry program has been installed
under the default filename (which is system dependant) or use the
option `pinentry-program' to specify the full name of that program. It
is often useful to install a symbolic link from the actual used
pinentry (e.g. `/usr/bin/pinentry-gtk') to the expected one (e.g.
`/usr/bin/pinentry').

*Note Option Index::,for an index to `GPG-AGENT''s commands and options.

* Menu:

* Agent Commands:: List of all commands.
* Agent Options:: List of all options.
* Agent Configuration:: Configuration files.
* Agent Signals:: Use of some signals.
* Agent Examples:: Some usage examples.
* Agent Protocol:: The protocol the agent uses.

File: gnupg.info, Node: Agent Commands, Next: Agent Options, Up: Invoking GPG-AGENT

2.1 Commands
============

Commands are not distinguished from options except for the fact that
only one command is allowed.

`--version'
Print the program version and licensing information. Note that
you cannot abbreviate this command.

`--help'
`-h'
Print a usage message summarizing the most useful command-line
options. Note that you cannot abbreviate this command.

`--dump-options'
Print a list of all available options and commands. Note that you
cannot abbreviate this command.

`--server'
Run in server mode and wait for commands on the `stdin'. The
default mode is to create a socket and listen for commands there.

`--daemon [COMMAND LINE]'
Start the gpg-agent as a daemon; that is, detach it from the
console and run it in the background. Because `gpg-agent' prints
out important information required for further use, a common way of
invoking gpg-agent is: `eval $(gpg-agent --daemon)' to setup the
environment variables. The option `--write-env-file' is another
way commonly used to do this. Yet another way is creating a new
process as a child of gpg-agent: `gpg-agent --daemon /bin/sh'.
This way you get a new shell with the environment setup properly;
if you exit from this shell, gpg-agent terminates as well.

File: gnupg.info, Node: Agent Options, Next: Agent Configuration, Prev: Agent Commands, Up: Invoking GPG-AGENT

2.2 Option Summary
==================

`--options FILE'
Reads configuration from FILE instead of from the default per-user
configuration file. The default configuration file is named
`gpg-agent.conf' and expected in the `.gnupg' directory directly
below the home directory of the user.

`--homedir DIR'
Set the name of the home directory to DIR. If this option is not
used, the home directory defaults to `~/.gnupg'. It is only
recognized when given on the command line. It also overrides any
home directory stated through the environment variable `GNUPGHOME'
or (on W32 systems) by means of the Registry entry
HKCU\SOFTWARE\GNU\GNUPG:HOMEDIR.

`-v'

`--verbose'
Outputs additional information while running. You can increase
the verbosity by giving several verbose commands to `gpgsm', such
as `-vv'.

`-q'

`--quiet'
Try to be as quiet as possible.

`--batch'
Don't invoke a pinentry or do any other thing requiring human
interaction.

`--faked-system-time EPOCH'
This option is only useful for testing; it sets the system time
back or forth to EPOCH which is the number of seconds elapsed
since the year 1970.

`--debug-level LEVEL'
Select the debug level for investigating problems. LEVEL may be a
numeric value or a keyword:

`none'
No debugging at all. A value of less than 1 may be used
instead of the keyword.

`basic'
Some basic debug messages. A value between 1 and 2 may be
used instead of the keyword.

`advanced'
More verbose debug messages. A value between 3 and 5 may be
used instead of the keyword.

`expert'
Even more detailed messages. A value between 6 and 8 may be
used instead of the keyword.

`guru'
All of the debug messages you can get. A value greater than 8
may be used instead of the keyword. The creation of hash
tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They
are however carefully selected to best aid in debugging.

`--debug FLAGS'
This option is only useful for debugging and the behaviour may
change at any time without notice. FLAGS are bit encoded and may
be given in usual C-Syntax. The currently defined bits are:

`0 (1)'
X.509 or OpenPGP protocol related data

`1 (2)'
values of big number integers

`2 (4)'
low level crypto operations

`5 (32)'
memory allocation

`6 (64)'
caching

`7 (128)'
show memory statistics.

`9 (512)'
write hashed data to files named `dbgmd-000*'

`10 (1024)'
trace Assuan protocol

`12 (4096)'
bypass all certificate validation

`--debug-all'
Same as `--debug=0xffffffff'

`--debug-wait N'
When running in server mode, wait N seconds before entering the
actual processing loop and print the pid. This gives time to
attach a debugger.

`--no-detach'
Don't detach the process from the console. This is mainly useful
for debugging.

`-s'
`--sh'
`-c'
`--csh'
Format the info output in daemon mode for use with the standard
Bourne shell or the C-shell respectively. The default is to guess
it based on the environment variable `SHELL' which is correct in
almost all cases.

`--write-env-file FILE'
Often it is required to connect to the agent from a process not
being an inferior of `gpg-agent' and thus the environment variable
with the socket name is not available. To help setting up those
variables in other sessions, this option may be used to write the
information into FILE. If FILE is not specified the default name
`${HOME}/.gpg-agent-info' will be used. The format is suitable to
be evaluated by a Bourne shell like in this simple example:

eval $(cat FILE)
eval $(cut -d= -f 1 < FILE | xargs echo export)

`--no-grab'
Tell the pinentry not to grab the keyboard and mouse. This option
should in general not be used to avoid X-sniffing attacks.

`--log-file FILE'
Append all logging output to FILE. This is very helpful in seeing
what the agent actually does. If neither a log file nor a log file
descriptor has been set on a Windows platform, the Registry entry
`HKCU\Software\GNU\GnuPG:DefaultLogFile', if set, is used to
specify the logging output.

`--allow-mark-trusted'
Allow clients to mark keys as trusted, i.e. put them into the
`trustlist.txt' file. This is by default not allowed to make it
harder for users to inadvertently accept Root-CA keys.

`--ignore-cache-for-signing'
This option will let `gpg-agent' bypass the passphrase cache for
all signing operation. Note that there is also a per-session
option to control this behaviour but this command line option
takes precedence.

`--default-cache-ttl N'
Set the time a cache entry is valid to N seconds. The default is
600 seconds.

`--default-cache-ttl-ssh N'
Set the time a cache entry used for SSH keys is valid to N
seconds. The default is 1800 seconds.

`--max-cache-ttl N'
Set the maximum time a cache entry is valid to N seconds. After
this time a cache entry will be expired even if it has been
accessed recently. The default is 2 hours (7200 seconds).

`--max-cache-ttl-ssh N'
Set the maximum time a cache entry used for SSH keys is valid to N
seconds. After this time a cache entry will be expired even if it
has been accessed recently. The default is 2 hours (7200 seconds).

`--enforce-passphrase-constraints'
Enforce the passphrase constraints by not allowing the user to
bypass them using the "Take it anyway" button.

`--min-passphrase-len N'
Set the minimal length of a passphrase. When entering a new
passphrase shorter than this value a warning will be displayed.
Defaults to 8.

`--min-passphrase-nonalpha N'
Set the minimal number of digits or special characters required in
a passphrase. When entering a new passphrase with less than this
number of digits or special characters a warning will be
displayed. Defaults to 1.

`--check-passphrase-pattern FILE'
Check the passphrase against the pattern given in FILE. When
entering a new passphrase matching one of these pattern a warning
will be displayed. FILE should be an absolute filename. The
default is not to use any pattern file.

Security note: It is known that checking a passphrase against a
list of pattern or even against a complete dictionary is not very
effective to enforce good passphrases. Users will soon figure up
ways to bypass such a policy. A better policy is to educate users
on good security behavior and optionally to run a passphrase
cracker regularly on all users passphrases to catch the very
simple ones.

`--max-passphrase-days N'
Ask the user to change the passphrase if N days have passed since
the last change. With `--enforce-passphrase-constraints' set the
user may not bypass this check.

`--enable-passphrase-history'
This option does nothing yet.

`--pinentry-program FILENAME'
Use program FILENAME as the PIN entry. The default is installation
dependent.

`--pinentry-touch-file FILENAME'
By default the filename of the socket gpg-agent is listening for
requests is passed to Pinentry, so that it can touch that file
before exiting (it does this only in curses mode). This option
changes the file passed to Pinentry to FILENAME. The special name
`/dev/null' may be used to completely disable this feature. Note
that Pinentry will not create that file, it will only change the
modification and access time.

`--scdaemon-program FILENAME'
Use program FILENAME as the Smartcard daemon. The default is
installation dependent and can be shown with the `gpgconf' command.

`--disable-scdaemon'
Do not make use of the scdaemon tool. This option has the effect
of disabling the ability to do smartcard operations. Note, that
enabling this option at runtime does not kill an already forked
scdaemon.

`--use-standard-socket'
`--no-use-standard-socket'
By enabling this option `gpg-agent' will listen on the socket
named `S.gpg-agent', located in the home directory, and not create
a random socket below a temporary directory. Tools connecting to
`gpg-agent' should first try to connect to the socket given in
environment variable GPG_AGENT_INFO and then fall back to this
socket. This option may not be used if the home directory is
mounted on a remote file system which does not support special
files like fifos or sockets. Note, that `--use-standard-socket'
is the default on Windows systems. The default may be changed at
build time. It is possible to test at runtime whether the agent
has been configured for use with the standard socket by issuing
the command `gpg-agent --use-standard-socket-p' which returns
success if the standard socket option has been enabled.

`--display STRING'
`--ttyname STRING'
`--ttytype STRING'
`--lc-ctype STRING'
`--lc-messages STRING'
`--xauthority STRING'
These options are used with the server mode to pass localization
information.

`--keep-tty'
`--keep-display'
Ignore requests to change the current `tty' or X window system's
`DISPLAY' variable respectively. This is useful to lock the
pinentry to pop up at the `tty' or display you started the agent.

`--enable-ssh-support'
Enable the OpenSSH Agent protocol.

In this mode of operation, the agent does not only implement the
gpg-agent protocol, but also the agent protocol used by OpenSSH
(through a separate socket). Consequently, it should be possible
to use the gpg-agent as a drop-in replacement for the well known
ssh-agent.

SSH Keys, which are to be used through the agent, need to be added
to the gpg-agent initially through the ssh-add utility. When a
key is added, ssh-add will ask for the password of the provided
key file and send the unprotected key material to the agent; this
causes the gpg-agent to ask for a passphrase, which is to be used
for encrypting the newly received key and storing it in a
gpg-agent specific directory.

Once a key has been added to the gpg-agent this way, the gpg-agent
will be ready to use the key.

Note: in case the gpg-agent receives a signature request, the user
might need to be prompted for a passphrase, which is necessary for
decrypting the stored key. Since the ssh-agent protocol does not
contain a mechanism for telling the agent on which
display/terminal it is running, gpg-agent's ssh-support will use
the TTY or X display where gpg-agent has been started. To switch
this display to the current one, the following command may be used:

gpg-connect-agent updatestartuptty /bye

Although all GnuPG components try to start the gpg-agent as
needed, this is not possible for the ssh support because ssh does
not know about it. Thus if no GnuPG tool which accesses the agent
has been run, there is no guarantee that ssh is abale to use
gpg-agent for authentication. To fix this you may start gpg-agent
if needed using this simple command:

gpg-connect-agent /bye

Adding the `--verbose' shows the progress of starting the agent.

All the long options may also be given in the configuration file
after stripping off the two leading dashes.

File: gnupg.info, Node: Agent Configuration, Next: Agent Signals, Prev: Agent Options, Up: Invoking GPG-AGENT

2.3 Configuration
=================

There are a few configuration files needed for the operation of the
agent. By default they may all be found in the current home directory
(*note option --homedir::).

`gpg-agent.conf'
This is the standard configuration file read by `gpg-agent' on
startup. It may contain any valid long option; the leading two
dashes may not be entered and the option may not be abbreviated.
This file is also read after a `SIGHUP' however only a few
options will actually have an effect. This default name may be
changed on the command line (*note option --options::). You
should backup this file.

`trustlist.txt'
This is the list of trusted keys. You should backup this file.

Comment lines, indicated by a leading hash mark, as well as empty
lines are ignored. To mark a key as trusted you need to enter its
fingerprint followed by a space and a capital letter `S'. Colons
may optionally be used to separate the bytes of a fingerprint;
this allows to cut and paste the fingerprint from a key listing
output. If the line is prefixed with a `!' the key is
explicitly marked as not trusted.

Here is an example where two keys are marked as ultimately trusted
and one as not trusted:

# CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
A6935DD34EF3087973C706FC311AA2CCF733765B S

# CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S

# CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
!14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S

Before entering a key into this file, you need to ensure its
authenticity. How to do this depends on your organisation; your
administrator might have already entered those keys which are
deemed trustworthy enough into this file. Places where to look
for the fingerprint of a root certificate are letters received
from the CA or the website of the CA (after making 100% sure that
this is indeed the website of that CA). You may want to consider
allowing interactive updates of this file by using the *Note
option --allow-mark-trusted::. This is however not as secure as
maintaining this file manually. It is even advisable to change
the permissions to read-only so that this file can't be changed
inadvertently.

As a special feature a line `include-default' will include a global
list of trusted certificates (e.g. `/etc/gnupg/trustlist.txt').
This global list is also used if the local list is not available.

It is possible to add further flags after the `S' for use by the
caller:

`relax'
Relax checking of some root certificate requirements. As of
now this flag allows the use of root certificates with a
missing basicConstraints attribute (despite that it is a MUST
for CA certificates) and disables CRL checking for the root
certificate.

`cm'
If validation of a certificate finally issued by a CA with
this flag set fails, try again using the chain validation
model.

`sshcontrol'
This file is used when support for the secure shell agent protocol
has been enabled (*note option --enable-ssh-support::). Only keys
present in this file are used in the SSH protocol. You should
backup this file.

The `ssh-add' tool may be used to add new entries to this file;
you may also add them manually. Comment lines, indicated by a
leading hash mark, as well as empty lines are ignored. An entry
starts with optional whitespace, followed by the keygrip of the
key given as 40 hex digits, optionally followed by the caching TTL
in seconds and another optional field for arbitrary flags. A
non-zero TTL overrides the global default as set by
`--default-cache-ttl-ssh'.

The only flag support is `confirm'. If this flag is found for a
key, each use of the key will pop up a pinentry to confirm the use
of that key. The flag is automatically set if a new key was
loaded into `gpg-agent' using the option `-c' of the `ssh-add'
command.

The keygrip may be prefixed with a `!' to disable an entry entry.

The following example lists exactly one key. Note that keys
available through a OpenPGP smartcard in the active smartcard
reader are implicitly added to this list; i.e. there is no need to
list them.

# Key added on: 2011-07-20 20:38:46
# Fingerprint: 5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm

`private-keys-v1.d/'
This is the directory where gpg-agent stores the private keys.
Each key is stored in a file with the name made up of the
keygrip and the suffix `key'. You should backup all files in
this directory and take great care to keep this backup closed
away.

Note that on larger installations, it is useful to put predefined
files into the directory `/etc/skel/.gnupg/' so that newly created
users start up with a working configuration. For existing users the a
small helper script is provided to create these files (*note
addgnupghome::).

File: gnupg.info, Node: Agent Signals, Next: Agent Examples, Prev: Agent Configuration, Up: Invoking GPG-AGENT

2.4 Use of some signals.
========================

A running `gpg-agent' may be controlled by signals, i.e. using the
`kill' command to send a signal to the process.

Here is a list of supported signals:

`SIGHUP'
This signal flushes all cached passphrases and if the program has
been started with a configuration file, the configuration file is
read again. Only certain options are honored: `quiet', `verbose',
`debug', `debug-all', `debug-level', `no-grab',
`pinentry-program', `default-cache-ttl', `max-cache-ttl',
`ignore-cache-for-signing', `allow-mark-trusted',
`disable-scdaemon', and `disable-check-own-socket'.
`scdaemon-program' is also supported but due to the current
implementation, which calls the scdaemon only once, it is not of
much use unless you manually kill the scdaemon.

`SIGTERM'
Shuts down the process but waits until all current requests are
fulfilled. If the process has received 3 of these signals and
requests are still pending, a shutdown is forced.

`SIGINT'
Shuts down the process immediately.

`SIGUSR1'
Dump internal information to the log file.

`SIGUSR2'
This signal is used for internal purposes.

File: gnupg.info, Node: Agent Examples, Next: Agent Protocol, Prev: Agent Signals, Up: Invoking GPG-AGENT

2.5 Examples
============

The usual way to invoke `gpg-agent' is

$ eval $(gpg-agent --daemon)

An alternative way is by replacing `ssh-agent' with `gpg-agent'. If
for example `ssh-agent' is started as part of the Xsession
initialization, you may simply replace `ssh-agent' by a script like:

#!/bin/sh

exec /usr/local/bin/gpg-agent --enable-ssh-support --daemon \
--write-env-file ${HOME}/.gpg-agent-info "$@"

and add something like (for Bourne shells)

if [ -f "${HOME}/.gpg-agent-info" ]; then
. "${HOME}/.gpg-agent-info"
export GPG_AGENT_INFO
export SSH_AUTH_SOCK
fi

to your shell initialization file (e.g. `~/.bashrc').

File: gnupg.info, Node: Agent Protocol, Prev: Agent Examples, Up: Invoking GPG-AGENT

2.6 Agent's Assuan Protocol
===========================

Note: this section does only document the protocol, which is used by
GnuPG components; it does not deal with the ssh-agent protocol.

The `gpg-agent' should be started by the login shell and set an
environment variable to tell clients about the socket to be used.
Clients should deny to access an agent with a socket name which does
not match its own configuration. An application may choose to start an
instance of the gpgagent if it does not figure that any has been
started; it should not do this if a gpgagent is running but not usable.
Because `gpg-agent' can only be used in background mode, no special
command line option is required to activate the use of the protocol.

To identify a key we use a thing called keygrip which is the SHA-1
hash of an canonical encoded S-Expression of the public key as used in
Libgcrypt. For the purpose of this interface the keygrip is given as a
hex string. The advantage of using this and not the hash of a
certificate is that it will be possible to use the same keypair for
different protocols, thereby saving space on the token used to keep the
secret keys.

* Menu:

* Agent PKDECRYPT:: Decrypting a session key
* Agent PKSIGN:: Signing a Hash
* Agent GENKEY:: Generating a Key
* Agent IMPORT:: Importing a Secret Key
* Agent EXPORT:: Exporting a Secret Key
* Agent ISTRUSTED:: Importing a Root Certificate
* Agent GET_PASSPHRASE:: Ask for a passphrase
* Agent CLEAR_PASSPHRASE:: Expire a cached passphrase
* Agent GET_CONFIRMATION:: Ask for confirmation
* Agent HAVEKEY:: Check whether a key is available
* Agent LEARN:: Register a smartcard
* Agent PASSWD:: Change a Passphrase
* Agent UPDATESTARTUPTTY:: Change the Standard Display
* Agent GETEVENTCOUNTER:: Get the Event Counters
* Agent GETINFO:: Return information about the process
* Agent OPTION:: Set options for the session

File: gnupg.info, Node: Agent PKDECRYPT, Next: Agent PKSIGN, Up: Agent Protocol

2.6.1 Decrypting a session key
------------------------------

The client asks the server to decrypt a session key. The encrypted
session key should have all information needed to select the
appropriate secret key or to delegate it to a smartcard.

SETKEY <keyGrip>

Tell the server about the key to be used for decryption. If this is
not used, `gpg-agent' may try to figure out the key by trying to
decrypt the message with each key available.

PKDECRYPT

The agent checks whether this command is allowed and then does an
INQUIRY to get the ciphertext the client should then send the cipher
text.

S: INQUIRE CIPHERTEXT
C: D (xxxxxx
C: D xxxx)
C: END

Please note that the server may send status info lines while reading
the data lines from the client. The data send is a SPKI like S-Exp with
this structure:

(enc-val
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>)))

Where algo is a string with the name of the algorithm; see the
libgcrypt documentation for a list of valid algorithms. The number and
names of the parameters depend on the algorithm. The agent does return
an error if there is an inconsistency.

If the decryption was successful the decrypted data is returned by
means of "D" lines.

Here is an example session:

C: PKDECRYPT
S: INQUIRE CIPHERTEXT
C: D (enc-val elg (a 349324324)
C: D (b 3F444677CA)))
C: END
S: # session key follows
S: S PADDING 0
S: D (value 1234567890ABCDEF0)
S: OK descryption successful

The â€œPADDINGâ€ status line is only send if gpg-agent can tell what
kind of padding is used. As of now only the value 0 is used to indicate
that the padding has been removed.

File: gnupg.info, Node: Agent PKSIGN, Next: Agent GENKEY, Prev: Agent PKDECRYPT, Up: Agent Protocol

2.6.2 Signing a Hash
--------------------

The client ask the agent to sign a given hash value. A default key
will be chosen if no key has been set. To set a key a client first
uses:

SIGKEY <keyGrip>

This can be used multiple times to create multiple signature, the
list of keys is reset with the next PKSIGN command or a RESET. The
server test whether the key is a valid key to sign something and
responds with okay.

SETHASH --hash=<name>|<algo> <hexstring>

The client can use this command to tell the server about the data
<hexstring> (which usually is a hash) to be signed. <algo> is the
decimal encoded hash algorithm number as used by Libgcrypt. Either
<algo> or -hash=<name> must be given. Valid names for <name> are:

`sha1'

`sha256'

`rmd160'

`md5'

`tls-md5sha1'

The actual signing is done using

PKSIGN <options>

Options are not yet defined, but my later be used to choose among
different algorithms. The agent does then some checks, asks for the
passphrase and as a result the server returns the signature as an SPKI
like S-expression in "D" lines:

(sig-val
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>)))

The operation is affected by the option

OPTION use-cache-for-signing=0|1

The default of `1' uses the cache. Setting this option to `0' will
lead `gpg-agent' to ignore the passphrase cache. Note, that there is
also a global command line option for `gpg-agent' to globally disable
the caching.

Here is an example session:

C: SIGKEY <keyGrip>
S: OK key available
C: SIGKEY <keyGrip>
S: OK key available
C: PKSIGN
S: # I did ask the user whether he really wants to sign
S: # I did ask the user for the passphrase
S: INQUIRE HASHVAL
C: D ABCDEF012345678901234
C: END
S: # signature follows
S: D (sig-val rsa (s 45435453654612121212))
S: OK

File: gnupg.info, Node: Agent GENKEY, Next: Agent IMPORT, Prev: Agent PKSIGN, Up: Agent Protocol

2.6.3 Generating a Key
----------------------

This is used to create a new keypair and store the secret key inside the
active PSE -- which is in most cases a Soft-PSE. An not yet defined
option allows to choose the storage location. To get the secret key out
of the PSE, a special export tool has to be used.

GENKEY

Invokes the key generation process and the server will then inquire
on the generation parameters, like:

S: INQUIRE KEYPARM
C: D (genkey (rsa (nbits 1024)))
C: END

The format of the key parameters which depends on the algorithm is of
the form:

(genkey
(algo
(parameter_name_1 ....)
....
(parameter_name_n ....)))

If everything succeeds, the server returns the *public key* in a SPKI
like S-Expression like this:

(public-key
(rsa
(n <mpi>)
(e <mpi>)))

Here is an example session:

C: GENKEY
S: INQUIRE KEYPARM
C: D (genkey (rsa (nbits 1024)))
C: END
S: D (public-key
S: D (rsa (n 326487324683264) (e 10001)))
S OK key created

File: gnupg.info, Node: Agent IMPORT, Next: Agent EXPORT, Prev: Agent GENKEY, Up: Agent Protocol

2.6.4 Importing a Secret Key
----------------------------

This operation is not yet supported by GpgAgent. Specialized tools are
to be used for this.

There is no actual need because we can expect that secret keys
created by a 3rd party are stored on a smartcard. If we have generated
the key ourself, we do not need to import it.

File: gnupg.info, Node: Agent EXPORT, Next: Agent ISTRUSTED, Prev: Agent IMPORT, Up: Agent Protocol

2.6.5 Export a Secret Key
-------------------------

Not implemented.

Should be done by an extra tool.

File: gnupg.info, Node: Agent ISTRUSTED, Next: Agent GET_PASSPHRASE, Prev: Agent EXPORT, Up: Agent Protocol

2.6.6 Importing a Root Certificate
----------------------------------

Actually we do not import a Root Cert but provide a way to validate any
piece of data by storing its Hash along with a description and an
identifier in the PSE. Here is the interface description:

ISTRUSTED <fingerprint>

Check whether the OpenPGP primary key or the X.509 certificate with
the given fingerprint is an ultimately trusted key or a trusted Root CA
certificate. The fingerprint should be given as a hexstring (without
any blanks or colons or whatever in between) and may be left padded with
00 in case of an MD5 fingerprint. GPGAgent will answer with:

The key is in the table of trusted keys.

ERR 304 (Not Trusted)

The key is not in this table.

Gpg needs the entire list of trusted keys to maintain the web of
trust; the following command is therefore quite helpful:

LISTTRUSTED

GpgAgent returns a list of trusted keys line by line:

S: D 000000001234454556565656677878AF2F1ECCFF P
S: D 340387563485634856435645634856438576457A P
S: D FEDC6532453745367FD83474357495743757435D S
S: OK

The first item on a line is the hexified fingerprint where MD5
fingerprints are `00' padded to the left and the second item is a flag
to indicate the type of key (so that gpg is able to only take care of
PGP keys). P = OpenPGP, S = S/MIME. A client should ignore the rest
of the line, so that we can extend the format in the future.

Finally a client should be able to mark a key as trusted:

MARKTRUSTED FINGERPRINT "P"|"S"

The server will then pop up a window to ask the user whether she
really trusts this key. For this it will probably ask for a text to be
displayed like this:

S: INQUIRE TRUSTDESC
C: D Do you trust the key with the fingerprint @FPR@
C: D bla fasel blurb.
C: END
S: OK

Known sequences with the pattern @foo@ are replaced according to this
table:

`@FPR16@'
Format the fingerprint according to gpg rules for a v3 keys.

`@FPR20@'
Format the fingerprint according to gpg rules for a v4 keys.

`@FPR@'
Choose an appropriate format to format the fingerprint.

`@@'
Replaced by a single `@'

File: gnupg.info, Node: Agent GET_PASSPHRASE, Next: Agent CLEAR_PASSPHRASE, Prev: Agent ISTRUSTED, Up: Agent Protocol

2.6.7 Ask for a passphrase
--------------------------

This function is usually used to ask for a passphrase to be used for
conventional encryption, but may also be used by programs which need
special handling of passphrases. This command uses a syntax which helps
clients to use the agent with minimum effort.

GET_PASSPHRASE [--data] [--check] [--no-ask] [--repeat[=N]] [--qualitybar] CACHE_ID [ERROR_MESSAGE PROMPT DESCRIPTION]

CACHE_ID is expected to be a string used to identify a cached
passphrase. Use a `X' to bypass the cache. With no other arguments
the agent returns a cached passphrase or an error. By convention
either the hexified fingerprint of the key shall be used for CACHE_ID
or an arbitrary string prefixed with the name of the calling
application and a colon: Like `gpg:somestring'.

ERROR_MESSAGE is either a single `X' for no error message or a
string to be shown as an error message like (e.g. "invalid
passphrase"). Blanks must be percent escaped or replaced by `+''.

PROMPT is either a single `X' for a default prompt or the text to be
shown as the prompt. Blanks must be percent escaped or replaced by `+'.

DESCRIPTION is a text shown above the entry field. Blanks must be
percent escaped or replaced by `+'.

The agent either returns with an error or with a OK followed by the
hex encoded passphrase. Note that the length of the strings is
implicitly limited by the maximum length of a command. If the option
`--data' is used, the passphrase is not returned on the OK line but by
regular data lines; this is the preferred method.

If the option `--check' is used, the standard passphrase constraints
checks are applied. A check is not done if the passphrase has been
found in the cache.

If the option `--no-ask' is used and the passphrase is not in the
cache the user will not be asked to enter a passphrase but the error
code `GPG_ERR_NO_DATA' is returned.

If the option `--qualitybar' is used and a minimum passphrase length
has been configured, a visual indication of the entered passphrase
quality is shown.

CLEAR_PASSPHRASE CACHE_ID

may be used to invalidate the cache entry for a passphrase. The
function returns with OK even when there is no cached passphrase.

File: gnupg.info, Node: Agent CLEAR_PASSPHRASE, Next: Agent GET_CONFIRMATION, Prev: Agent GET_PASSPHRASE, Up: Agent Protocol

2.6.8 Remove a cached passphrase
--------------------------------

Use this command to remove a cached passphrase.

CLEAR_PASSPHRASE <cache_id>

File: gnupg.info, Node: Agent GET_CONFIRMATION, Next: Agent HAVEKEY, Prev: Agent CLEAR_PASSPHRASE, Up: Agent Protocol

2.6.9 Ask for confirmation
--------------------------

This command may be used to ask for a simple confirmation by presenting
a text and 2 buttons: Okay and Cancel.

GET_CONFIRMATION DESCRIPTION

DESCRIPTIONis displayed along with a Okay and Cancel button. Blanks
must be percent escaped or replaced by `+'. A `X' may be used to
display confirmation dialog with a default text.

The agent either returns with an error or with a OK. Note, that the
length of DESCRIPTION is implicitly limited by the maximum length of a
command.

File: gnupg.info, Node: Agent HAVEKEY, Next: Agent LEARN, Prev: Agent GET_CONFIRMATION, Up: Agent Protocol

2.6.10 Check whether a key is available
---------------------------------------

This can be used to see whether a secret key is available. It does not
return any information on whether the key is somehow protected.

HAVEKEY KEYGRIPS

The agent answers either with OK or `No_Secret_Key' (208). The
caller may want to check for other error codes as well. More than one
keygrip may be given. In this case the command returns success if at
least one of the keygrips corresponds to an available secret key.

File: gnupg.info, Node: Agent LEARN, Next: Agent PASSWD, Prev: Agent HAVEKEY, Up: Agent Protocol

2.6.11 Register a smartcard
---------------------------

LEARN [--send]

This command is used to register a smartcard. With the -send option
given the certificates are send back.

File: gnupg.info, Node: Agent PASSWD, Next: Agent UPDATESTARTUPTTY, Prev: Agent LEARN, Up: Agent Protocol

2.6.12 Change a Passphrase
--------------------------

PASSWD KEYGRIP

This command is used to interactively change the passphrase of the
key identified by the hex string KEYGRIP.

File: gnupg.info, Node: Agent UPDATESTARTUPTTY, Next: Agent GETEVENTCOUNTER, Prev: Agent PASSWD, Up: Agent Protocol

2.6.13 Change the standard display
----------------------------------

UPDATESTARTUPTTY

Set the startup TTY and X-DISPLAY variables to the values of this
session. This command is useful to direct future pinentry invocations
to another screen. It is only required because there is no way in the
ssh-agent protocol to convey this information.

File: gnupg.info, Node: Agent GETEVENTCOUNTER, Next: Agent GETINFO, Prev: Agent UPDATESTARTUPTTY, Up: Agent Protocol

2.6.14 Get the Event Counters
-----------------------------

GETEVENTCOUNTER

This function return one status line with the current values of the
event counters. The event counters are useful to avoid polling by
delaying a poll until something has changed. The values are decimal
numbers in the range `0' to `UINT_MAX' and wrapping around to 0. The
actual values should not be relied upon; they shall only be used to
detect a change.

The currently defined counters are are:
`ANY'
Incremented with any change of any of the other counters.

`KEY'
Incremented for added or removed private keys.

`CARD'
Incremented for changes of the card readers stati.

File: gnupg.info, Node: Agent GETINFO, Next: Agent OPTION, Prev: Agent GETEVENTCOUNTER, Up: Agent Protocol

2.6.15 Return information about the process
-------------------------------------------

This is a multipurpose function to return a variety of information.

GETINFO WHAT

The value of WHAT specifies the kind of information returned:
`version'
Return the version of the program.

`pid'
Return the process id of the process.

`socket_name'
Return the name of the socket used to connect the agent.

`ssh_socket_name'
Return the name of the socket used for SSH connections. If SSH
support has not been enabled the error `GPG_ERR_NO_DATA' will be
returned.

File: gnupg.info, Node: Agent OPTION, Prev: Agent GETINFO, Up: Agent Protocol

2.6.16 Set options for the session
----------------------------------

Here is a list of session options which are not yet described with
other commands. The general syntax for an Assuan option is:

OPTION KEY=VALUE

Supported KEYs are:

`agent-awareness'
This may be used to tell gpg-agent of which gpg-agent version the
client is aware of. gpg-agent uses this information to enable
features which might break older clients.

`putenv'
Change the session's environment to be used for the Pinentry.
Valid values are:

`NAME'
Delete envvar NAME

`NAME='
Set envvar NAME to the empty string

`NAME=VALUE'
Set envvar NAME to the string VALUE.

`use-cache-for-signing'
See Assuan command `PKSIGN'.

`allow-pinentry-notify'
This does not need any value. It is used to enable the
PINENTRY_LAUNCHED inquiry.

File: gnupg.info, Node: Invoking GPG, Next: Invoking GPGSM, Prev: Invoking GPG-AGENT, Up: Top

3 Invoking GPG
**************

`gpg2' is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a
tool to provide digital encryption and signing services using the
OpenPGP standard. `gpg2' features complete key management and all bells
and whistles you can expect from a decent OpenPGP implementation.

In contrast to the standalone version `gpg', which is more suited
for server and embedded platforms, this version is commonly installed
under the name `gpg2' and more targeted to the desktop as it requires
several other modules to be installed. The standalone version will be
kept maintained and it is possible to install both versions on the same
system. If you need to use different configuration files, you should
make use of something like `gpg.conf-2' instead of just `gpg.conf'.

Documentation for the old standard `gpg' is available as a man page
and at *note GnuPG 1: (gpg)Top.

*Note Option Index::, for an index to `gpg2''s commands and options.

* Menu:

* GPG Commands:: List of all commands.
* GPG Options:: List of all options.
* GPG Configuration:: Configuration files.
* GPG Examples:: Some usage examples.

Developer information:
* Unattended Usage of GPG:: Using `gpg' from other programs.

File: gnupg.info, Node: GPG Commands, Next: GPG Options, Up: Invoking GPG

3.1 Commands
============

Commands are not distinguished from options except for the fact that
only one command is allowed.

`gpg2' may be run with no commands, in which case it will perform a
reasonable action depending on the type of file it is given as input
(an encrypted message is decrypted, a signature is verified, a file
containing keys is listed).

Please remember that option as well as command parsing stops as soon
as a non-option is encountered, you can explicitly stop parsing by
using the special option `--'.

* Menu:

* General GPG Commands:: Commands not specific to the functionality.
* Operational GPG Commands:: Commands to select the type of operation.
* OpenPGP Key Management:: How to manage your keys.

File: gnupg.info, Node: General GPG Commands, Next: Operational GPG Commands, Up: GPG Commands

3.1.1 Commands not specific to the function
-------------------------------------------

`--version'
Print the program version and licensing information. Note that you
cannot abbreviate this command.

`--help'
`-h'
Print a usage message summarizing the most useful command line
options. Note that you cannot abbreviate this command.

`--warranty'
Print warranty information.

`--dump-options'
Print a list of all available options and commands. Note that you
cannot abbreviate this command.

File: gnupg.info, Node: Operational GPG Commands, Next: OpenPGP Key Management, Prev: General GPG Commands, Up: GPG Commands

3.1.2 Commands to select the type of operation
----------------------------------------------

`--sign'
`-s'
Make a signature. This command may be combined with `--encrypt'
(for a signed and encrypted message), `--symmetric' (for a signed
and symmetrically encrypted message), or `--encrypt' and
`--symmetric' together (for a signed message that may be decrypted
via a secret key or a passphrase). The key to be used for signing
is chosen by default or can be set with the `--local-user' and
`--default-key' options.

`--clearsign'
Make a clear text signature. The content in a clear text
signature is readable without any special software. OpenPGP
software is only needed to verify the signature. Clear text
signatures may modify end-of-line whitespace for platform
independence and are not intended to be reversible. The key to be
used for signing is chosen by default or can be set with the
`--local-user' and `--default-key' options.

`--detach-sign'
`-b'
Make a detached signature.

`--encrypt'
`-e'
Encrypt data. This option may be combined with `--sign' (for a
signed and encrypted message), `--symmetric' (for a message that
may be decrypted via a secret key or a passphrase), or `--sign'
and `--symmetric' together (for a signed message that may be
decrypted via a secret key or a passphrase).

`--symmetric'
`-c'
Encrypt with a symmetric cipher using a passphrase. The default
symmetric cipher used is CAST5, but may be chosen with the
`--cipher-algo' option. This option may be combined with `--sign'
(for a signed and symmetrically encrypted message), `--encrypt'
(for a message that may be decrypted via a secret key or a
passphrase), or `--sign' and `--encrypt' together (for a signed
message that may be decrypted via a secret key or a passphrase).

`--store'
Store only (make a simple RFC1991 literal data packet).

`--decrypt'
`-d'
Decrypt the file given on the command line (or STDIN if no file is
specified) and write it to STDOUT (or the file specified with
`--output'). If the decrypted file is signed, the signature is also
verified. This command differs from the default operation, as it
never writes to the filename which is included in the file and it
rejects files which don't begin with an encrypted message.

`--verify'
Assume that the first argument is a signed file or a detached
signature and verify it without generating any output. With no
arguments, the signature packet is read from STDIN. If only a
sigfile is given, it may be a complete signature or a detached
signature, in which case the signed stuff is expected in a file
without the ".sig" or ".asc" extension. With more than 1
argument, the first should be a detached signature and the
remaining files are the signed stuff. To read the signed stuff
from STDIN, use `-' as the second filename. For security reasons
a detached signature cannot read the signed material from STDIN
without denoting it in the above way.

Note: When verifying a cleartext signature, `gpg' verifies only
what makes up the cleartext signed data and not any extra data
outside of the cleartext signature or header lines following
directly the dash marker line. The option `--output' may be used
to write out the actual signed data; but there are other pitfalls
with this format as well. It is suggested to avoid cleartext
signatures in favor of detached signatures.

`--multifile'
This modifies certain other commands to accept multiple files for
processing on the command line or read from STDIN with each
filename on a separate line. This allows for many files to be
processed at once. `--multifile' may currently be used along with
`--verify', `--encrypt', and `--decrypt'. Note that `--multifile
--verify' may not be used with detached signatures.

`--verify-files'
Identical to `--multifile --verify'.

`--encrypt-files'
Identical to `--multifile --encrypt'.

`--decrypt-files'
Identical to `--multifile --decrypt'.

`--list-keys'
`-k'
`--list-public-keys'
List all keys from the public keyrings, or just the keys given on
the command line.

Avoid using the output of this command in scripts or other
programs as it is likely to change as GnuPG changes. See
`--with-colons' for a machine-parseable key listing command that
is appropriate for use in scripts and other programs.

`--list-secret-keys'
`-K'
List all keys from the secret keyrings, or just the ones given on
the command line. A `#' after the letters `sec' means that the
secret key is not usable (for example, if it was created via
`--export-secret-subkeys').

`--list-sigs'
Same as `--list-keys', but the signatures are listed too. This
command has the same effect as using `--list-keys' with
`--with-sig-list'.

For each signature listed, there are several flags in between the
"sig" tag and keyid. These flags give additional information about
each signature. From left to right, they are the numbers 1-3 for
certificate check level (see `--ask-cert-level'), "L" for a local
or non-exportable signature (see `--lsign-key'), "R" for a
nonRevocable signature (see the `--edit-key' command "nrsign"),
"P" for a signature that contains a policy URL (see
`--cert-policy-url'), "N" for a signature that contains a notation
(see `--cert-notation'), "X" for an eXpired signature (see
`--ask-cert-expire'), and the numbers 1-9 or "T" for 10 and above
to indicate trust signature levels (see the `--edit-key' command
"tsign").

`--check-sigs'
Same as `--list-sigs', but the signatures are verified. Note that
for performance reasons the revocation status of a signing key is
not shown. This command has the same effect as using
`--list-keys' with `--with-sig-check'.

The status of the verification is indicated by a flag directly
following the "sig" tag (and thus before the flags described above
for `--list-sigs'). A "!" indicates that the signature has been
successfully verified, a "-" denotes a bad signature and a "%" is
used if an error occurred while checking the signature (e.g. a non
supported algorithm).

`--locate-keys'
Locate the keys given as arguments. This command basically uses
the same algorithm as used when locating keys for encryption or
signing and may thus be used to see what keys `gpg2' might use. In
particular external methods as defined by `--auto-key-locate' may
be used to locate a key. Only public keys are listed.

`--fingerprint'
List all keys (or the specified ones) along with their
fingerprints. This is the same output as `--list-keys' but with
the additional output of a line with the fingerprint. May also be
combined with `--list-sigs' or `--check-sigs'. If this command is
given twice, the fingerprints of all secondary keys are listed too.

`--list-packets'
List only the sequence of packets. This is mainly useful for
debugging.

`--card-edit'
Present a menu to work with a smartcard. The subcommand "help"
provides an overview on available commands. For a detailed
description, please see the Card HOWTO at
http://www.gnupg.org/documentation/howtos.html#GnuPG-cardHOWTO .

`--card-status'
Show the content of the smart card.

`--change-pin'
Present a menu to allow changing the PIN of a smartcard. This
functionality is also available as the subcommand "passwd" with the
`--card-edit' command.

`--delete-key `name''
Remove key from the public keyring. In batch mode either `--yes' is
required or the key must be specified by fingerprint. This is a
safeguard against accidental deletion of multiple keys.

`--delete-secret-key `name''
Remove key from the secret keyring. In batch mode the key must be
specified by fingerprint.

`--delete-secret-and-public-key `name''
Same as `--delete-key', but if a secret key exists, it will be
removed first. In batch mode the key must be specified by
fingerprint.

`--export'
Either export all keys from all keyrings (default keyrings and
those registered via option `--keyring'), or if at least one name
is given, those of the given name. The new keyring is written to
STDOUT or to the file given with option `--output'. Use together
with `--armor' to mail those keys.

`--send-keys `key IDs''
Similar to `--export' but sends the keys to a keyserver.
Fingerprints may be used instead of key IDs. Option `--keyserver'
must be used to give the name of this keyserver. Don't send your
complete keyring to a keyserver -- select only those keys which
are new or changed by you. If no key IDs are given, `gpg' does
nothing.

`--export-secret-keys'
`--export-secret-subkeys'
Same as `--export', but exports the secret keys instead. This is
normally not very useful and a security risk. The second form of
the command has the special property to render the secret part of
the primary key useless; this is a GNU extension to OpenPGP and
other implementations can not be expected to successfully import
such a key. See the option `--simple-sk-checksum' if you want to
import such an exported key with an older OpenPGP implementation.

`--import'
`--fast-import'
Import/merge keys. This adds the given keys to the keyring. The
fast version is currently just a synonym.

There are a few other options which control how this command works.
Most notable here is the `--import-options merge-only' option
which does not insert new keys but does only the merging of new
signatures, user-IDs and subkeys.

`--recv-keys `key IDs''
Import the keys with the given key IDs from a keyserver. Option
`--keyserver' must be used to give the name of this keyserver.

`--refresh-keys'
Request updates from a keyserver for keys that already exist on the
local keyring. This is useful for updating a key with the latest
signatures, user IDs, etc. Calling this with no arguments will
refresh the entire keyring. Option `--keyserver' must be used to
give the name of the keyserver for all keys that do not have
preferred keyservers set (see `--keyserver-options
honor-keyserver-url').

`--search-keys `names''
Search the keyserver for the given names. Multiple names given
here will be joined together to create the search string for the
keyserver. Option `--keyserver' must be used to give the name of
this keyserver. Keyservers that support different search methods
allow using the syntax specified in "How to specify a user ID"
below. Note that different keyserver types support different
search methods. Currently only LDAP supports them all.

`--fetch-keys `URIs''
Retrieve keys located at the specified URIs. Note that different
installations of GnuPG may support different protocols (HTTP, FTP,
LDAP, etc.)

`--update-trustdb'
Do trust database maintenance. This command iterates over all keys
and builds the Web of Trust. This is an interactive command
because it may have to ask for the "ownertrust" values for keys.
The user has to give an estimation of how far she trusts the owner
of the displayed key to correctly certify (sign) other keys. GnuPG
only asks for the ownertrust value if it has not yet been assigned
to a key. Using the `--edit-key' menu, the assigned value can be
changed at any time.

`--check-trustdb'
Do trust database maintenance without user interaction. From time
to time the trust database must be updated so that expired keys or
signatures and the resulting changes in the Web of Trust can be
tracked. Normally, GnuPG will calculate when this is required and
do it automatically unless `--no-auto-check-trustdb' is set. This
command can be used to force a trust database check at any time.
The processing is identical to that of `--update-trustdb' but it
skips keys with a not yet defined "ownertrust".

For use with cron jobs, this command can be used together with
`--batch' in which case the trust database check is done only if a
check is needed. To force a run even in batch mode add the option
`--yes'.

`--export-ownertrust'
Send the ownertrust values to STDOUT. This is useful for backup
purposes as these values are the only ones which can't be
re-created from a corrupted trustdb. Example:
gpg2 --export-ownertrust > otrust.txt

`--import-ownertrust'
Update the trustdb with the ownertrust values stored in `files' (or
STDIN if not given); existing values will be overwritten. In case
of a severely damaged trustdb and if you have a recent backup of
the ownertrust values (e.g. in the file `otrust.txt', you may
re-create the trustdb using these commands:
cd ~/.gnupg
rm trustdb.gpg
gpg2 --import-ownertrust < otrust.txt

`--rebuild-keydb-caches'
When updating from version 1.0.6 to 1.0.7 this command should be
used to create signature caches in the keyring. It might be handy
in other situations too.

`--print-md `algo''
`--print-mds'
Print message digest of algorithm ALGO for all given files or
STDIN. With the second form (or a deprecated "*" as algo) digests
for all available algorithms are printed.

`--gen-random `0|1|2' `count''
Emit COUNT random bytes of the given quality level 0, 1 or 2. If
COUNT is not given or zero, an endless sequence of random bytes
will be emitted. If used with `--armor' the output will be base64
encoded. PLEASE, don't use this command unless you know what you
are doing; it may remove precious entropy from the system!

`--gen-prime `mode' `bits''
Use the source, Luke :-). The output format is still subject to
change.

`--enarmor'

`--dearmor'
Pack or unpack an arbitrary input into/from an OpenPGP ASCII armor.
This is a GnuPG extension to OpenPGP and in general not very
useful.

File: gnupg.info, Node: OpenPGP Key Management, Prev: Operational GPG Commands, Up: GPG Commands

3.1.3 How to manage your keys
-----------------------------

This section explains the main commands for key management

`--gen-key'
Generate a new key pair. This command is normally only used
interactively.

There is an experimental feature which allows you to create keys in
batch mode. See the file `doc/DETAILS' in the source distribution
on how to use this.

`--gen-revoke `name''
Generate a revocation certificate for the complete key. To revoke
a subkey or a signature, use the `--edit' command.

`--desig-revoke `name''
Generate a designated revocation certificate for a key. This
allows a user (with the permission of the keyholder) to revoke
someone else's key.

`--edit-key'
Present a menu which enables you to do most of the key management
related tasks. It expects the specification of a key on the
command line.

uid `n'
Toggle selection of user ID or photographic user ID with
index `n'. Use `*' to select all and `0' to deselect all.

key `n'
Toggle selection of subkey with index `n'. Use `*' to
select all and `0' to deselect all.

sign
Make a signature on key of user `name' If the key is not yet
signed by the default user (or the users given with -u), the
program displays the information of the key again, together
with its fingerprint and asks whether it should be signed.
This question is repeated for all users specified with -u.

lsign
Same as "sign" but the signature is marked as non-exportable
and will therefore never be used by others. This may be
used to make keys valid only in the local environment.

nrsign
Same as "sign" but the signature is marked as non-revocable
and can therefore never be revoked.

tsign
Make a trust signature. This is a signature that combines the
notions of certification (like a regular signature), and
trust (like the "trust" command). It is generally only
useful in distinct communities or groups.

Note that "l" (for local / non-exportable), "nr" (for
non-revocable, and "t" (for trust) may be freely mixed and
prefixed to "sign" to create a signature of any type desired.

delsig
Delete a signature. Note that it is not possible to retract a
signature, once it has been send to the public (i.e. to a
keyserver). In that case you better use `revsig'.

revsig
Revoke a signature. For every signature which has been
generated by one of the secret keys, GnuPG asks whether a
revocation certificate should be generated.

check
Check the signatures on all selected user IDs.

adduid
Create an additional user ID.

addphoto
Create a photographic user ID. This will prompt for a JPEG
file that will be embedded into the user ID. Note that a
very large JPEG will make for a very large key. Also note
that some programs will display your JPEG unchanged
(GnuPG), and some programs will scale it to fit in a dialog
box (PGP).

showphoto
Display the selected photographic user ID.

deluid
Delete a user ID or photographic user ID. Note that it is not
possible to retract a user id, once it has been send to the
public (i.e. to a keyserver). In that case you better use
`revuid'.

revuid
Revoke a user ID or photographic user ID.

primary
Flag the current user id as the primary one, removes the
primary user id flag from all other user ids and sets the
timestamp of all affected self-signatures one second ahead.
Note that setting a photo user ID as primary makes it
primary over other photo user IDs, and setting a regular
user ID as primary makes it primary over other regular user
IDs.

keyserver
Set a preferred keyserver for the specified user ID(s). This
allows other users to know where you prefer they get your
key from. See `--keyserver-options honor-keyserver-url' for
more on how this works. Setting a value of "none" removes
an existing preferred keyserver.

notation
Set a name=value notation for the specified user ID(s). See
`--cert-notation' for more on how this works. Setting a value
of "none" removes all notations, setting a notation
prefixed with a minus sign (-) removes that notation, and
setting a notation name (without the =value) prefixed with
a minus sign removes all notations with that name.

pref
List preferences from the selected user ID. This shows the
actual preferences, without including any implied
preferences.

showpref
More verbose preferences listing for the selected user ID.
This shows the preferences in effect by including the
implied preferences of 3DES (cipher), SHA-1 (digest), and
Uncompressed (compression) if they are not already included
in the preference list. In addition, the preferred
keyserver and signature notations (if any) are shown.

setpref `string'
Set the list of user ID preferences to `string' for all (or
just the selected) user IDs. Calling setpref with no
arguments sets the preference list to the default (either
built-in or set via `--default-preference-list'), and
calling setpref with "none" as the argument sets an empty
preference list. Use `gpg2 --version' to get a list of
available algorithms. Note that while you can change the
preferences on an attribute user ID (aka "photo ID"), GnuPG
does not select keys via attribute user IDs so these
preferences will not be used by GnuPG.

When setting preferences, you should list the algorithms in
the order which you'd like to see them used by someone else
when encrypting a message to your key. If you don't
include 3DES, it will be automatically added at the end.
Note that there are many factors that go into choosing an
algorithm (for example, your key may not be the only
recipient), and so the remote OpenPGP application being used
to send to you may or may not follow your exact chosen
order for a given message. It will, however, only choose
an algorithm that is present on the preference list of
every recipient key. See also the INTEROPERABILITY WITH
OTHER OPENPGP PROGRAMS section below.

addkey
Add a subkey to this key.

addcardkey
Generate a subkey on a card and add it to this key.

keytocard
Transfer the selected secret subkey (or the primary key if no
subkey has been selected) to a smartcard. The secret key in
the keyring will be replaced by a stub if the key could be
stored successfully on the card and you use the save
command later. Only certain key types may be transferred to
the card. A sub menu allows you to select on what card to
store the key. Note that it is not possible to get that key
back from the card - if the card gets broken your secret
key will be lost unless you have a backup somewhere.

bkuptocard `file'
Restore the given file to a card. This command may be used to
restore a backup key (as generated during card
initialization) to a new card. In almost all cases this
will be the encryption key. You should use this command
only with the corresponding public key and make sure that the
file given as argument is indeed the backup to restore. You
should then select 2 to restore as encryption key. You
will first be asked to enter the passphrase of the backup
key and then for the Admin PIN of the card.

delkey
Remove a subkey (secondart key). Note that it is not possible
to retract a subkey, once it has been send to the public
(i.e. to a keyserver). In that case you better use
`revkey'.

revkey
Revoke a subkey.

expire
Change the key or subkey expiration time. If a subkey is
selected, the expiration time of this subkey will be
changed. With no selection, the key expiration of the
primary key is changed.

trust
Change the owner trust value for the key. This updates the
trust-db immediately and no save is required.

disable
enable
Disable or enable an entire key. A disabled key can not
normally be used for encryption.

addrevoker
Add a designated revoker to the key. This takes one optional
argument: "sensitive". If a designated revoker is marked as
sensitive, it will not be exported by default (see
export-options).

passwd
Change the passphrase of the secret key.

toggle
Toggle between public and secret key listing.

clean
Compact (by removing all signatures except the selfsig) any
user ID that is no longer usable (e.g. revoked, or
expired). Then, remove any signatures that are not usable
by the trust calculations. Specifically, this removes any
signature that does not validate, any signature that is
superseded by a later signature, revoked signatures, and
signatures issued by keys that are not present on the keyring.

minimize
Make the key as small as possible. This removes all
signatures from each user ID except for the most recent
self-signature.

cross-certify
Add cross-certification signatures to signing subkeys that
may not currently have them. Cross-certification signatures
protect against a subtle attack against signing subkeys. See
`--require-cross-certification'. All new keys generated have
this signature by default, so this option is only useful to
bring older keys up to date.

save
Save all changes to the key rings and quit.

quit
Quit the program without updating the key rings.

The listing shows you the key with its secondary keys and all user
ids. The primary user id is indicated by a dot, and selected keys
or user ids are indicated by an asterisk. The trust value is
displayed with the primary key: the first is the assigned owner
trust and the second is the calculated trust value. Letters are
used for the values:

-
No ownertrust assigned / not yet calculated.

e
Trust calculation has failed; probably due to an expired
key.

q
Not enough information for calculation.

n
Never trust this key.

m
Marginally trusted.

f
Fully trusted.

u
Ultimately trusted.

`--sign-key `name''
Signs a public key with your secret key. This is a shortcut
version of the subcommand "sign" from `--edit'.

`--lsign-key `name''
Signs a public key with your secret key but marks it as
non-exportable. This is a shortcut version of the subcommand
"lsign" from `--edit-key'.

`--passwd USER_ID'
Change the passphrase of the secret key belonging to the
certificate specified as USER_ID. This is a shortcut for the
sub-command `passwd' of the edit key menu.

File: gnupg.info, Node: GPG Options, Next: GPG Configuration, Prev: GPG Commands, Up: Invoking GPG

3.2 Option Summary
==================

`gpg2' features a bunch of options to control the exact behaviour and
to change the default configuration.

* Menu:

* GPG Configuration Options:: How to change the configuration.
* GPG Key related Options:: Key related options.
* GPG Input and Output:: Input and Output.
* OpenPGP Options:: OpenPGP protocol specific options.
* Compliance Options:: Compliance options.
* GPG Esoteric Options:: Doing things one usually don't want to do.
* Deprecated Options:: Deprecated options.

Long options can be put in an options file (default
"~/.gnupg/gpg.conf"). Short option names will not work - for example,
"armor" is a valid option for the options file, while "a" is not. Do not
write the 2 dashes, but simply the name of the option and any required
arguments. Lines with a hash ('#') as the first non-white-space
character are ignored. Commands may be put in this file too, but that is
not generally useful as the command will execute automatically with
every execution of gpg.

Please remember that option parsing stops as soon as a non-option is
encountered, you can explicitly stop parsing by using the special option
`--'.

File: gnupg.info, Node: GPG Configuration Options, Next: GPG Key related Options, Up: GPG Options

3.2.1 How to change the configuration
-------------------------------------

These options are used to change the configuration and are usually found
in the option file.

`--default-key NAME'
Use NAME as the default key to sign with. If this option is not
used, the default key is the first key found in the secret keyring.
Note that `-u' or `--local-user' overrides this option.

`--default-recipient NAME'
Use NAME as default recipient if option `--recipient' is not used
and don't ask if this is a valid one. NAME must be non-empty.

`--default-recipient-self'
Use the default key as default recipient if option `--recipient'
is not used and don't ask if this is a valid one. The default key
is the first one from the secret keyring or the one set with
`--default-key'.

`--no-default-recipient'
Reset `--default-recipient' and `--default-recipient-self'.

`-v, --verbose'
Give more information during processing. If used twice, the input
data is listed in detail.

`--no-verbose'
Reset verbose level to 0.

`-q, --quiet'
Try to be as quiet as possible.

`--batch'
`--no-batch'
Use batch mode. Never ask, do not allow interactive commands.
`--no-batch' disables this option. Note that even with a filename
given on the command line, gpg might still need to read from STDIN
(in particular if gpg figures that the input is a detached
signature and no data file has been specified). Thus if you do
not want to feed data via STDIN, you should connect STDIN to
`/dev/null'.

`--no-tty'
Make sure that the TTY (terminal) is never used for any output.
This option is needed in some cases because GnuPG sometimes prints
warnings to the TTY even if `--batch' is used.

`--yes'
Assume "yes" on most questions.

`--no'
Assume "no" on most questions.

`--list-options `parameters''
This is a space or comma delimited string that gives options used
when listing keys and signatures (that is, `--list-keys',
`--list-sigs', `--list-public-keys', `--list-secret-keys', and the
`--edit-key' functions). Options can be prepended with a `no-'
(after the two dashes) to give the opposite meaning. The options
are:

show-photos
Causes `--list-keys', `--list-sigs', `--list-public-keys',
and `--list-secret-keys' to display any photo IDs attached
to the key. Defaults to no. See also `--photo-viewer'.
Does not work with `--with-colons': see `--attribute-fd'
for the appropriate way to get photo data for scripts and
other frontends.

show-policy-urls
Show policy URLs in the `--list-sigs' or `--check-sigs'
listings. Defaults to no.

show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature notations
in the `--list-sigs' or `--check-sigs' listings. Defaults
to no.

show-keyserver-urls
Show any preferred keyserver URL in the `--list-sigs' or
`--check-sigs' listings. Defaults to no.

show-uid-validity
Display the calculated validity of user IDs during key
listings. Defaults to no.

show-unusable-uids
Show revoked and expired user IDs in key listings. Defaults
to no.

show-unusable-subkeys
Show revoked and expired subkeys in key listings. Defaults to
no.

show-keyring
Display the keyring name at the head of key listings to show
which keyring a given key resides on. Defaults to no.

show-sig-expire
Show signature expiration dates (if any) during `--list-sigs'
or `--check-sigs' listings. Defaults to no.

show-sig-subpackets
Include signature subpackets in the key listing. This option
can take an optional argument list of the subpackets to
list. If no argument is passed, list all subpackets.
Defaults to no. This option is only meaningful when using
`--with-colons' along with `--list-sigs' or `--check-sigs'.

`--verify-options `parameters''
This is a space or comma delimited string that gives options used
when verifying signatures. Options can be prepended with a `no-'
to give the opposite meaning. The options are:

show-photos
Display any photo IDs present on the key that issued the
signature. Defaults to no. See also `--photo-viewer'.

show-policy-urls
Show policy URLs in the signature being verified. Defaults to
no.

show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature notations
in the signature being verified. Defaults to IETF standard.

show-keyserver-urls
Show any preferred keyserver URL in the signature being
verified. Defaults to no.

show-uid-validity
Display the calculated validity of the user IDs on the key
that issued the signature. Defaults to no.

show-unusable-uids
Show revoked and expired user IDs during signature
verification. Defaults to no.

show-primary-uid-only
Show only the primary user ID during signature verification.
That is all the AKA lines as well as photo Ids are not
shown with the signature verification status.

pka-lookups
Enable PKA lookups to verify sender addresses. Note that PKA
is based on DNS, and so enabling this option may disclose
information on when and what signatures are verified or to
whom data is encrypted. This is similar to the "web bug"
described for the auto-key-retrieve feature.

pka-trust-increase
Raise the trust in a signature to full if the signature
passes PKA validation. This option is only meaningful if
pka-lookups is set.

`--enable-dsa2'
`--disable-dsa2'
Enable hash truncation for all DSA keys even for old DSA Keys up to
1024 bit. This is also the default with `--openpgp'. Note that
older versions of GnuPG also required this flag to allow the
generation of DSA larger than 1024 bit.

`--photo-viewer `string''
This is the command line that should be run to view a photo ID.
"%i" will be expanded to a filename containing the photo. "%I"
does the same, except the file will not be deleted once the viewer
exits. Other flags are "%k" for the key ID, "%K" for the long key
ID, "%f" for the key fingerprint, "%t" for the extension of the
image type (e.g. "jpg"), "%T" for the MIME type of the image (e.g.
"image/jpeg"), "%v" for the single-character calculated validity
of the image being viewed (e.g. "f"), "%V" for the calculated
validity as a string (e.g. "full"), and "%%" for an actual
percent sign. If neither %i or %I are present, then the photo will
be supplied to the viewer on standard input.

The default viewer is "xloadimage -fork -quiet -title 'KeyID 0x%k'
STDIN". Note that if your image viewer program is not secure, then
executing it from GnuPG does not make it secure.

`--exec-path `string''
Sets a list of directories to search for photo viewers and
keyserver helpers. If not provided, keyserver helpers use the
compiled-in default directory, and photo viewers use the $PATH
environment variable. Note, that on W32 system this value is
ignored when searching for keyserver helpers.

`--keyring `file''
Add `file' to the current list of keyrings. If `file' begins with
a tilde and a slash, these are replaced by the $HOME directory. If
the filename does not contain a slash, it is assumed to be in the
GnuPG home directory ("~/.gnupg" if `--homedir' or $GNUPGHOME is
not used).

Note that this adds a keyring to the current list. If the intent
is to use the specified keyring alone, use `--keyring' along with
`--no-default-keyring'.

`--secret-keyring `file''
Same as `--keyring' but for the secret keyrings.

`--primary-keyring `file''
Designate `file' as the primary public keyring. This means that
newly imported keys (via `--import' or keyserver `--recv-from')
will go to this keyring.

`--trustdb-name `file''
Use `file' instead of the default trustdb. If `file' begins with a
tilde and a slash, these are replaced by the $HOME directory. If
the filename does not contain a slash, it is assumed to be in the
GnuPG home directory (`~/.gnupg' if `--homedir' or $GNUPGHOME is
not used).

`--display-charset `name''
Set the name of the native character set. This is used to convert
some informational strings like user IDs to the proper UTF-8
encoding. Note that this has nothing to do with the character set
of data to be encrypted or signed; GnuPG does not recode
user-supplied data. If this option is not used, the default
character set is determined from the current locale. A verbosity
level of 3 shows the chosen set. Valid values for `name' are:

iso-8859-1
This is the Latin 1 set.

iso-8859-2
The Latin 2 set.

iso-8859-15
This is currently an alias for the Latin 1 set.

koi8-r
The usual Russian set (rfc1489).

utf-8
Bypass all translations and assume that the OS uses native
UTF-8 encoding.

`--utf8-strings'
`--no-utf8-strings'
Assume that command line arguments are given as UTF8 strings. The
default (`--no-utf8-strings') is to assume that arguments are
encoded in the character set as specified by `--display-charset'.
These options affect all following arguments. Both options may be
used multiple times.

`--options `file''
Read options from `file' and do not try to read them from the
default options file in the homedir (see `--homedir'). This option
is ignored if used in an options file.

`--no-options'
Shortcut for `--options /dev/null'. This option is detected before
an attempt to open an option file. Using this option will also
prevent the creation of a `~/.gnupg' homedir.

`-z `n''
`--compress-level `n''
`--bzip2-compress-level `n''
Set compression level to `n' for the ZIP and ZLIB compression
algorithms. The default is to use the default compression level of
zlib (normally 6). `--bzip2-compress-level' sets the compression
level for the BZIP2 compression algorithm (defaulting to 6 as
well). This is a different option from `--compress-level' since
BZIP2 uses a significant amount of memory for each additional
compression level. `-z' sets both. A value of 0 for `n' disables
compression.

`--bzip2-decompress-lowmem'
Use a different decompression method for BZIP2 compressed files.
This alternate method uses a bit more than half the memory, but
also runs at half the speed. This is useful under extreme low
memory circumstances when the file was originally compressed at a
high `--bzip2-compress-level'.

`--mangle-dos-filenames'
`--no-mangle-dos-filenames'
Older version of Windows cannot handle filenames with more than one
dot. `--mangle-dos-filenames' causes GnuPG to replace (rather than
add to) the extension of an output filename to avoid this problem.
This option is off by default and has no effect on non-Windows
platforms.

`--ask-cert-level'
`--no-ask-cert-level'
When making a key signature, prompt for a certification level. If
this option is not specified, the certification level used is set
via `--default-cert-level'. See `--default-cert-level' for
information on the specific levels and how they are used.
`--no-ask-cert-level' disables this option. This option defaults
to no.

`--default-cert-level `n''
The default to use for the check level when signing a key.

0 means you make no particular claim as to how carefully you
verified the key.

1 means you believe the key is owned by the person who claims to
own it but you could not, or did not verify the key at all. This is
useful for a "persona" verification, where you sign the key of a
pseudonymous user.

2 means you did casual verification of the key. For example, this
could mean that you verified the key fingerprint and checked the
user ID on the key against a photo ID.

3 means you did extensive verification of the key. For example,
this could mean that you verified the key fingerprint with the
owner of the key in person, and that you checked, by means of a
hard to forge document with a photo ID (such as a passport) that
the name of the key owner matches the name in the user ID on the
key, and finally that you verified (by exchange of email) that the
email address on the key belongs to the key owner.

Note that the examples given above for levels 2 and 3 are just
that: examples. In the end, it is up to you to decide just what
"casual" and "extensive" mean to you.

This option defaults to 0 (no particular claim).

`--min-cert-level'
When building the trust database, treat any signatures with a
certification level below this as invalid. Defaults to 2, which
disregards level 1 signatures. Note that level 0 "no particular
claim" signatures are always accepted.

`--trusted-key `long key ID''
Assume that the specified key (which must be given as a full 8
byte key ID) is as trustworthy as one of your own secret keys.
This option is useful if you don't want to keep your secret keys
(or one of them) online but still want to be able to check the
validity of a given recipient's or signator's key.

`--trust-model `pgp|classic|direct|always|auto''
Set what trust model GnuPG should follow. The models are:

pgp
This is the Web of Trust combined with trust signatures as
used in PGP 5.x and later. This is the default trust model
when creating a new trust database.

classic
This is the standard Web of Trust as used in PGP 2.x and
earlier.

direct
Key validity is set directly by the user and not calculated
via the Web of Trust.

always
Skip key validation and assume that used keys are always fully
trusted. You generally won't use this unless you are using
some external validation scheme. This option also
suppresses the "[uncertain]" tag printed with signature
checks when there is no evidence that the user ID is bound
to the key.

auto
Select the trust model depending on whatever the internal
trust database says. This is the default model if such a
database already exists.

`--auto-key-locate `parameters''
`--no-auto-key-locate'
GnuPG can automatically locate and retrieve keys as needed using
this option. This happens when encrypting to an email address (in
the "user AT example.com" form), and there are no user AT example.com
keys on the local keyring. This option takes any number of the
following mechanisms, in the order they are to be tried:

cert
Locate a key using DNS CERT, as specified in rfc4398.

pka
Locate a key using DNS PKA.

ldap
Using DNS Service Discovery, check the domain in question for
any LDAP keyservers to use. If this fails, attempt to
locate the key using the PGP Universal method of checking
`ldap://keys.(thedomain)'.

keyserver
Locate a key using whatever keyserver is defined using the
`--keyserver' option.

keyserver-URL
In addition, a keyserver URL as used in the `--keyserver'
option may be used here to query that particular keyserver.

local
Locate the key using the local keyrings. This mechanism
allows to select the order a local key lookup is done.
Thus using `--auto-key-locate local' is identical to
`--no-auto-key-locate'.

nodefault
This flag disables the standard local key lookup, done before
any of the mechanisms defined by the `--auto-key-locate'
are tried. The position of this mechanism in the list does
not matter. It is not required if `local' is also used.

`--keyid-format `short|0xshort|long|0xlong''
Select how to display key IDs. "short" is the traditional
8-character key ID. "long" is the more accurate (but less
convenient) 16-character key ID. Add an "0x" to either to include
an "0x" at the beginning of the key ID, as in 0x99242560. Note
that this option is ignored if the option -with-colons is used.

`--keyserver `name''
Use `name' as your keyserver. This is the server that
`--recv-keys', `--send-keys', and `--search-keys' will communicate
with to receive keys from, send keys to, and search for keys on.
The format of the `name' is a URI:
`scheme:[//]keyservername[:port]' The scheme is the type of
keyserver: "hkp" for the HTTP (or compatible) keyservers, "ldap"
for the LDAP keyservers, or "mailto" for the Graff email
keyserver. Note that your particular installation of GnuPG may
have other keyserver types available as well. Keyserver schemes
are case-insensitive. After the keyserver name, optional keyserver
configuration options may be provided. These are the same as the
global `--keyserver-options' from below, but apply only to this
particular keyserver.

Most keyservers synchronize with each other, so there is generally
no need to send keys to more than one server. The keyserver
`hkp://keys.gnupg.net' uses round robin DNS to give a different
keyserver each time you use it.

`--keyserver-options `name=value1 ''
This is a space or comma delimited string that gives options for
the keyserver. Options can be prefixed with a `no-' to give the
opposite meaning. Valid import-options or export-options may be
used here as well to apply to importing (`--recv-key') or exporting
(`--send-key') a key from a keyserver. While not all options are
available for all keyserver types, some common options are:

include-revoked
When searching for a key with `--search-keys', include keys
that are marked on the keyserver as revoked. Note that not
all keyservers differentiate between revoked and unrevoked
keys, and for such keyservers this option is meaningless.
Note also that most keyservers do not have cryptographic
verification of key revocations, and so turning this option
off may result in skipping keys that are incorrectly marked
as revoked.

include-disabled
When searching for a key with `--search-keys', include keys
that are marked on the keyserver as disabled. Note that
this option is not used with HKP keyservers.

auto-key-retrieve
This option enables the automatic retrieving of keys from a
keyserver when verifying signatures made by keys that are
not on the local keyring.

Note that this option makes a "web bug" like behavior
possible. Keyserver operators can see which keys you
request, so by sending you a message signed by a brand new
key (which you naturally will not have on your local
keyring), the operator can tell both your IP address and
the time when you verified the signature.

honor-keyserver-url
When using `--refresh-keys', if the key in question has a
preferred keyserver URL, then use that preferred keyserver
to refresh the key from. In addition, if auto-key-retrieve
is set, and the signature being verified has a preferred
keyserver URL, then use that preferred keyserver to fetch
the key from. Defaults to yes.

honor-pka-record
If auto-key-retrieve is set, and the signature being verified
has a PKA record, then use the PKA information to fetch the
key. Defaults to yes.

include-subkeys
When receiving a key, include subkeys as potential targets.
Note that this option is not used with HKP keyservers, as
they do not support retrieving keys by subkey id.

use-temp-files
On most Unix-like platforms, GnuPG communicates with the
keyserver helper program via pipes, which is the most
efficient method. This option forces GnuPG to use temporary
files to communicate. On some platforms (such as Win32 and
RISC OS), this option is always enabled.

keep-temp-files
If using `use-temp-files', do not delete the temp files after
using them. This option is useful to learn the keyserver
communication protocol by reading the temporary files.

verbose
Tell the keyserver helper program to be more verbose. This
option can be repeated multiple times to increase the
verbosity level.

timeout
Tell the keyserver helper program how long (in seconds) to
try and perform a keyserver action before giving up. Note
that performing multiple actions at the same time uses this
timeout value per action. For example, when retrieving
multiple keys via `--recv-keys', the timeout applies
separately to each key retrieval, and not to the
`--recv-keys' command as a whole. Defaults to 30 seconds.

http-proxy=`value'
Set the proxy to use for HTTP and HKP keyservers. This
overrides the "http_proxy" environment variable, if any.

max-cert-size
When retrieving a key via DNS CERT, only accept keys up to
this size. Defaults to 16384 bytes.

debug
Turn on debug output in the keyserver helper program. Note
that the details of debug output depends on which keyserver
helper program is being used, and in turn, on any libraries
that the keyserver helper program uses internally (libcurl,
openldap, etc).

check-cert
Enable certificate checking if the keyserver presents one
(for hkps or ldaps). Defaults to on.

ca-cert-file
Provide a certificate store to override the system default.
Only necessary if check-cert is enabled, and the keyserver
is using a certificate that is not present in a system
default certificate list.

Note that depending on the SSL library that the keyserver
helper is built with, this may actually be a directory or a
file.

`--completes-needed `n''
Number of completely trusted users to introduce a new key signer
(defaults to 1).

`--marginals-needed `n''
Number of marginally trusted users to introduce a new key signer
(defaults to 3)

`--max-cert-depth `n''
Maximum depth of a certification chain (default is 5).

`--simple-sk-checksum'
Secret keys are integrity protected by using a SHA-1 checksum. This
method is part of the upcoming enhanced OpenPGP specification but
GnuPG already uses it as a countermeasure against certain attacks.
Old applications don't understand this new format, so this option
may be used to switch back to the old behaviour. Using this option
bears a security risk. Note that using this option only takes
effect when the secret key is encrypted - the simplest way to make
this happen is to change the passphrase on the key (even changing
it to the same value is acceptable).

`--no-sig-cache'
Do not cache the verification status of key signatures. Caching
gives a much better performance in key listings. However, if you
suspect that your public keyring is not save against write
modifications, you can use this option to disable the caching. It
probably does not make sense to disable it because all kind of
damage can be done if someone else has write access to your public
keyring.

`--no-sig-create-check'
GnuPG normally verifies each signature right after creation to
protect against bugs and hardware malfunctions which could leak
out bits from the secret key. This extra verification needs some
time (about 115% for DSA keys), and so this option can be used to
disable it. However, due to the fact that the signature creation
needs manual interaction, this performance penalty does not matter
in most settings.

`--auto-check-trustdb'
`--no-auto-check-trustdb'
If GnuPG feels that its information about the Web of Trust has to
be updated, it automatically runs the `--check-trustdb' command
internally. This may be a time consuming process.
`--no-auto-check-trustdb' disables this option.

`--use-agent'
`--no-use-agent'
This is dummy option. `gpg2' always requires the agent.

`--gpg-agent-info'
This is dummy option. It has no effect when used with `gpg2'.

`--lock-once'
Lock the databases the first time a lock is requested and do not
release the lock until the process terminates.

`--lock-multiple'
Release the locks every time a lock is no longer needed. Use this
to override a previous `--lock-once' from a config file.

`--lock-never'
Disable locking entirely. This option should be used only in very
special environments, where it can be assured that only one process
is accessing those files. A bootable floppy with a stand-alone
encryption system will probably use this. Improper usage of this
option may lead to data and key corruption.

`--exit-on-status-write-error'
This option will cause write errors on the status FD to immediately
terminate the process. That should in fact be the default but it
never worked this way and thus we need an option to enable this,
so that the change won't break applications which close their end
of a status fd connected pipe too early. Using this option along
with `--enable-progress-filter' may be used to cleanly cancel long
running gpg operations.

`--limit-card-insert-tries `n''
With `n' greater than 0 the number of prompts asking to insert a
smartcard gets limited to N-1. Thus with a value of 1 gpg won't at
all ask to insert a card if none has been inserted at startup. This
option is useful in the configuration file in case an application
does not know about the smartcard support and waits ad infinitum
for an inserted card.

`--no-random-seed-file'
GnuPG uses a file to store its internal random pool over
invocations. This makes random generation faster; however
sometimes write operations are not desired. This option can be
used to achieve that with the cost of slower random generation.

`--no-greeting'
Suppress the initial copyright message.

`--no-secmem-warning'
Suppress the warning about "using insecure memory".

`--no-permission-warning'
Suppress the warning about unsafe file and home directory
(`--homedir') permissions. Note that the permission checks that
GnuPG performs are not intended to be authoritative, but rather
they simply warn about certain common permission problems. Do not
assume that the lack of a warning means that your system is secure.

Note that the warning for unsafe `--homedir' permissions cannot be
suppressed in the gpg.conf file, as this would allow an attacker to
place an unsafe gpg.conf file in place, and use this file to
suppress warnings about itself. The `--homedir' permissions
warning may only be suppressed on the command line.

`--no-mdc-warning'
Suppress the warning about missing MDC integrity protection.

`--require-secmem'
`--no-require-secmem'
Refuse to run if GnuPG cannot get secure memory. Defaults to no
(i.e. run, but give a warning).

`--require-cross-certification'
`--no-require-cross-certification'
When verifying a signature made from a subkey, ensure that the
cross certification "back signature" on the subkey is present and
valid. This protects against a subtle attack against subkeys that
can sign. Defaults to `--require-cross-certification' for `gpg2'.

`--expert'
`--no-expert'
Allow the user to do certain nonsensical or "silly" things like
signing an expired or revoked key, or certain potentially
incompatible things like generating unusual key types. This also
disables certain warning messages about potentially incompatible
actions. As the name implies, this option is for experts only. If
you don't fully understand the implications of what it allows you
to do, leave this off. `--no-expert' disables this option.

File: gnupg.info, Node: GPG Key related Options, Next: GPG Input and Output, Prev: GPG Configuration Options, Up: GPG Options

3.2.2 Key related options
-------------------------

`--recipient NAME'
`-r'
Encrypt for user id NAME. If this option or `--hidden-recipient'
is not specified, GnuPG asks for the user-id unless
`--default-recipient' is given.

`--hidden-recipient NAME'
`-R'
Encrypt for user ID NAME, but hide the key ID of this user's key.
This option helps to hide the receiver of the message and is a
limited countermeasure against traffic analysis. If this option or
`--recipient' is not specified, GnuPG asks for the user ID unless
`--default-recipient' is given.

`--encrypt-to `name''
Same as `--recipient' but this one is intended for use in the
options file and may be used with your own user-id as an
"encrypt-to-self". These keys are only used when there are other
recipients given either by use of `--recipient' or by the asked
user id. No trust checking is performed for these user ids and
even disabled keys can be used.

`--hidden-encrypt-to `name''
Same as `--hidden-recipient' but this one is intended for use in
the options file and may be used with your own user-id as a hidden
"encrypt-to-self". These keys are only used when there are other
recipients given either by use of `--recipient' or by the asked
user id. No trust checking is performed for these user ids and
even disabled keys can be used.

`--no-encrypt-to'
Disable the use of all `--encrypt-to' and `--hidden-encrypt-to'
keys.

`--group `name=value1 ''
Sets up a named group, which is similar to aliases in email
programs. Any time the group name is a recipient (`-r' or
`--recipient'), it will be expanded to the values specified.
Multiple groups with the same name are automatically merged into a
single group.

The values are `key IDs' or fingerprints, but any key description
is accepted. Note that a value with spaces in it will be treated as
two different values. Note also there is only one level of
expansion -- you cannot make an group that points to another
group. When used from the command line, it may be necessary to
quote the argument to this option to prevent the shell from
treating it as multiple arguments.

`--ungroup `name''
Remove a given entry from the `--group' list.

`--no-groups'
Remove all entries from the `--group' list.

`--local-user NAME'
`-u'
Use NAME as the key to sign with. Note that this option overrides
`--default-key'.

`--try-all-secrets'
Don't look at the key ID as stored in the message but try all
secret keys in turn to find the right decryption key. This option
forces the behaviour as used by anonymous recipients (created by
using `--throw-keyids' or `--hidden-recipient') and might come
handy in case where an encrypted message contains a bogus key ID.

`--skip-hidden-recipients'
`--no-skip-hidden-recipients'
During decryption skip all anonymous recipients. This option
helps in the case that people use the hidden recipients feature to
hide there own encrypt-to key from others. If oneself has many
secret keys this may lead to a major annoyance because all keys
are tried in turn to decrypt soemthing which was not really
intended for it. The drawback of this option is that it is
currently not possible to decrypt a message which includes real
anonymous recipients.

File: gnupg.info, Node: GPG Input and Output, Next: OpenPGP Options, Prev: GPG Key related Options, Up: GPG Options

3.2.3 Input and Output
----------------------

`--armor'
`-a'
Create ASCII armored output. The default is to create the binary
OpenPGP format.

`--no-armor'
Assume the input data is not in ASCII armored format.

`--output FILE'
`-o FILE'
Write output to FILE.

`--max-output `n''
This option sets a limit on the number of bytes that will be
generated when processing a file. Since OpenPGP supports various
levels of compression, it is possible that the plaintext of a
given message may be significantly larger than the original
OpenPGP message. While GnuPG works properly with such messages,
there is often a desire to set a maximum file size that will be
generated before processing is forced to stop by the OS limits.
Defaults to 0, which means "no limit".

`--import-options `parameters''
This is a space or comma delimited string that gives options for
importing keys. Options can be prepended with a `no-' to give the
opposite meaning. The options are:

import-local-sigs
Allow importing key signatures marked as "local". This is not
generally useful unless a shared keyring scheme is being
used. Defaults to no.

repair-pks-subkey-bug
During import, attempt to repair the damage caused by the PKS
keyserver bug (pre version 0.9.6) that mangles keys with
multiple subkeys. Note that this cannot completely repair
the damaged key as some crucial data is removed by the
keyserver, but it does at least give you back one subkey.
Defaults to no for regular `--import' and to yes for
keyserver `--recv-keys'.

merge-only
During import, allow key updates to existing keys, but do not
allow any new keys to be imported. Defaults to no.

import-clean
After import, compact (remove all signatures except the
self-signature) any user IDs from the new key that are not
usable. Then, remove any signatures from the new key that
are not usable. This includes signatures that were issued
by keys that are not present on the keyring. This option is
the same as running the `--edit-key' command "clean" after
import. Defaults to no.

import-minimal
Import the smallest key possible. This removes all signatures
except the most recent self-signature on each user ID. This
option is the same as running the `--edit-key' command
"minimize" after import. Defaults to no.

`--export-options `parameters''
This is a space or comma delimited string that gives options for
exporting keys. Options can be prepended with a `no-' to give the
opposite meaning. The options are:

export-local-sigs
Allow exporting key signatures marked as "local". This is not
generally useful unless a shared keyring scheme is being
used. Defaults to no.

export-attributes
Include attribute user IDs (photo IDs) while exporting. This
is useful to export keys if they are going to be used by an
OpenPGP program that does not accept attribute user IDs.
Defaults to yes.

export-sensitive-revkeys
Include designated revoker information that was marked as
"sensitive". Defaults to no.

export-reset-subkey-passwd
When using the `--export-secret-subkeys' command, this option
resets the passphrases for all exported subkeys to empty.
This is useful when the exported subkey is to be used on an
unattended machine where a passphrase doesn't necessarily
make sense. Defaults to no.

export-clean
Compact (remove all signatures from) user IDs on the key being
exported if the user IDs are not usable. Also, do not export
any signatures that are not usable. This includes
signatures that were issued by keys that are not present on
the keyring. This option is the same as running the
`--edit-key' command "clean" before export except that the
local copy of the key is not modified. Defaults to no.

export-minimal
Export the smallest key possible. This removes all signatures
except the most recent self-signature on each user ID. This
option is the same as running the `--edit-key' command
"minimize" before export except that the local copy of the
key is not modified. Defaults to no.

`--with-colons'
Print key listings delimited by colons. Note that the output will
be encoded in UTF-8 regardless of any `--display-charset' setting.
This format is useful when GnuPG is called from scripts and other
programs as it is easily machine parsed. The details of this
format are documented in the file `doc/DETAILS', which is included
in the GnuPG source distribution.

`--fixed-list-mode'
Do not merge primary user ID and primary key in `--with-colon'
listing mode and print all timestamps as seconds since 1970-01-01.
Since GnuPG 2.0.10, this mode is always used and thus this option
is obsolete; it does not harm to use it though.

`--with-fingerprint'
Same as the command `--fingerprint' but changes only the format of
the output and may be used together with another command.

File: gnupg.info, Node: OpenPGP Options, Next: Compliance Options, Prev: GPG Input and Output, Up: GPG Options

3.2.4 OpenPGP protocol specific options.
----------------------------------------

`-t, --textmode'
`--no-textmode'
Treat input files as text and store them in the OpenPGP canonical
text form with standard "CRLF" line endings. This also sets the
necessary flags to inform the recipient that the encrypted or
signed data is text and may need its line endings converted back
to whatever the local system uses. This option is useful when
communicating between two platforms that have different line
ending conventions (UNIX-like to Mac, Mac to Windows, etc).
`--no-textmode' disables this option, and is the default.

`--force-v3-sigs'
`--no-force-v3-sigs'
OpenPGP states that an implementation should generate v4 signatures
but PGP versions 5 through 7 only recognize v4 signatures on key
material. This option forces v3 signatures for signatures on data.
Note that this option implies `--no-ask-sig-expire', and unsets
`--sig-policy-url', `--sig-notation', and `--sig-keyserver-url',
as these features cannot be used with v3 signatures.
`--no-force-v3-sigs' disables this option. Defaults to no.

`--force-v4-certs'
`--no-force-v4-certs'
Always use v4 key signatures even on v3 keys. This option also
changes the default hash algorithm for v3 RSA keys from MD5 to
SHA-1. `--no-force-v4-certs' disables this option.

`--force-mdc'
Force the use of encryption with a modification detection code.
This is always used with the newer ciphers (those with a blocksize
greater than 64 bits), or if all of the recipient keys indicate
MDC support in their feature flags.

`--disable-mdc'
Disable the use of the modification detection code. Note that by
using this option, the encrypted message becomes vulnerable to a
message modification attack.

`--personal-cipher-preferences `string''
Set the list of personal cipher preferences to `string'. Use
`gpg2 --version' to get a list of available algorithms, and use
`none' to set no preference at all. This allows the user to
safely override the algorithm chosen by the recipient key
preferences, as GPG will only select an algorithm that is usable by
all recipients. The most highly ranked cipher in this list is also
used for the `--symmetric' encryption command.

`--personal-digest-preferences `string''
Set the list of personal digest preferences to `string'. Use
`gpg2 --version' to get a list of available algorithms, and use
`none' to set no preference at all. This allows the user to
safely override the algorithm chosen by the recipient key
preferences, as GPG will only select an algorithm that is usable by
all recipients. The most highly ranked digest algorithm in this
list is also used when signing without encryption (e.g.
`--clearsign' or `--sign').

`--personal-compress-preferences `string''
Set the list of personal compression preferences to `string'. Use
`gpg2 --version' to get a list of available algorithms, and use
`none' to set no preference at all. This allows the user to
safely override the algorithm chosen by the recipient key
preferences, as GPG will only select an algorithm that is usable
by all recipients. The most highly ranked compression algorithm
in this list is also used when there are no recipient keys to
consider (e.g. `--symmetric').

`--s2k-cipher-algo `name''
Use `name' as the cipher algorithm used to protect secret keys.
The default cipher is CAST5. This cipher is also used for
conventional encryption if `--personal-cipher-preferences' and
`--cipher-algo' is not given.

`--s2k-digest-algo `name''
Use `name' as the digest algorithm used to mangle the passphrases.
The default algorithm is SHA-1.

`--s2k-mode `n''
Selects how passphrases are mangled. If `n' is 0 a plain
passphrase (which is not recommended) will be used, a 1 adds a
salt to the passphrase and a 3 (the default) iterates the whole
process a number of times (see -s2k-count). Unless `--rfc1991' is
used, this mode is also used for conventional encryption.

`--s2k-count `n''
Specify how many times the passphrase mangling is repeated. This
value may range between 1024 and 65011712 inclusive. The default
is inquired from gpg-agent. Note that not all values in the
1024-65011712 range are legal and if an illegal value is selected,
GnuPG will round up to the nearest legal value. This option is
only meaningful if `--s2k-mode' is 3.

File: gnupg.info, Node: Compliance Options, Next: GPG Esoteric Options, Prev: OpenPGP Options, Up: GPG Options

3.2.5 Compliance options
------------------------

These options control what GnuPG is compliant to. Only one of these
options may be active at a time. Note that the default setting of this
is nearly always the correct one. See the INTEROPERABILITY WITH OTHER
OPENPGP PROGRAMS section below before using one of these options.

`--gnupg'
Use standard GnuPG behavior. This is essentially OpenPGP behavior
(see `--openpgp'), but with some additional workarounds for common
compatibility problems in different versions of PGP. This is the
default option, so it is not generally needed, but it may be
useful to override a different compliance option in the gpg.conf
file.

`--openpgp'
Reset all packet, cipher and digest options to strict OpenPGP
behavior. Use this option to reset all previous options like
`--s2k-*', `--cipher-algo', `--digest-algo' and `--compress-algo'
to OpenPGP compliant values. All PGP workarounds are disabled.

`--rfc4880'
Reset all packet, cipher and digest options to strict RFC-4880
behavior. Note that this is currently the same thing as
`--openpgp'.

`--rfc2440'
Reset all packet, cipher and digest options to strict RFC-2440
behavior.

`--rfc1991'
Try to be more RFC-1991 (PGP 2.x) compliant.

`--pgp2'
Set up all options to be as PGP 2.x compliant as possible, and
warn if an action is taken (e.g. encrypting to a non-RSA key) that
will create a message that PGP 2.x will not be able to handle.
Note that `PGP 2.x' here means `MIT PGP 2.6.2'. There are other
versions of PGP 2.x available, but the MIT release is a good
common baseline.

This option implies `--rfc1991 --disable-mdc --no-force-v4-certs
--escape-from-lines --force-v3-sigs --cipher-algo IDEA
--digest-algo MD5 --compress-algo ZIP'. It also disables
`--textmode' when encrypting.

`--pgp6'
Set up all options to be as PGP 6 compliant as possible. This
restricts you to the ciphers IDEA (if the IDEA plugin is
installed), 3DES, and CAST5, the hashes MD5, SHA1 and RIPEMD160,
and the compression algorithms none and ZIP. This also disables
-throw-keyids, and making signatures with signing subkeys as PGP 6
does not understand signatures made by signing subkeys.

This option implies `--disable-mdc --escape-from-lines
--force-v3-sigs'.

`--pgp7'
Set up all options to be as PGP 7 compliant as possible. This is
identical to `--pgp6' except that MDCs are not disabled, and the
list of allowable ciphers is expanded to add AES128, AES192,
AES256, and TWOFISH.

`--pgp8'
Set up all options to be as PGP 8 compliant as possible. PGP 8 is
a lot closer to the OpenPGP standard than previous versions of
PGP, so all this does is disable `--throw-keyids' and set
`--escape-from-lines'. All algorithms are allowed except for the
SHA224, SHA384, and SHA512 digests.

File: gnupg.info, Node: GPG Esoteric Options, Next: Deprecated Options, Prev: Compliance Options, Up: GPG Options

3.2.6 Doing things one usually doesn't want to do.
--------------------------------------------------

`-n'
`--dry-run'
Don't make any changes (this is not completely implemented).

`--list-only'
Changes the behaviour of some commands. This is like `--dry-run'
but different in some cases. The semantic of this command may be
extended in the future. Currently it only skips the actual
decryption pass and therefore enables a fast listing of the
encryption keys.

`-i'
`--interactive'
Prompt before overwriting any files.

`--debug-level LEVEL'
Select the debug level for investigating problems. LEVEL may be a
numeric value or by a keyword:

`none'
No debugging at all. A value of less than 1 may be used
instead of the keyword.

`basic'
Some basic debug messages. A value between 1 and 2 may be
used instead of the keyword.

`advanced'
More verbose debug messages. A value between 3 and 5 may be
used instead of the keyword.

`expert'
Even more detailed messages. A value between 6 and 8 may be
used instead of the keyword.

`guru'
All of the debug messages you can get. A value greater than 8
may be used instead of the keyword. The creation of hash
tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They
are however carefully selected to best aid in debugging.

`--debug FLAGS'
Set debugging flags. All flags are or-ed and FLAGS may be given in
C syntax (e.g. 0x0042).

`--debug-all'
Set all useful debugging flags.

`--faked-system-time EPOCH'
This option is only useful for testing; it sets the system time
back or forth to EPOCH which is the number of seconds elapsed
since the year 1970. Alternatively EPOCH may be given as a full
ISO time string (e.g. "20070924T154812").

`--enable-progress-filter'
Enable certain PROGRESS status outputs. This option allows
frontends to display a progress indicator while gpg is processing
larger files. There is a slight performance overhead using it.

`--status-fd `n''
Write special status strings to the file descriptor `n'. See the
file DETAILS in the documentation for a listing of them.

`--status-file `file''
Same as `--status-fd', except the status data is written to file
`file'.

`--logger-fd `n''
Write log output to file descriptor `n' and not to STDERR.

`--log-file `file''
`--logger-file `file''
Same as `--logger-fd', except the logger data is written to file
`file'. Note that `--log-file' is only implemented for GnuPG-2.

`--attribute-fd `n''
Write attribute subpackets to the file descriptor `n'. This is most
useful for use with `--status-fd', since the status messages are
needed to separate out the various subpackets from the stream
delivered to the file descriptor.

`--attribute-file `file''
Same as `--attribute-fd', except the attribute data is written to
file `file'.

`--comment `string''
`--no-comments'
Use `string' as a comment string in clear text signatures and ASCII
armored messages or keys (see `--armor'). The default behavior is
not to use a comment string. `--comment' may be repeated multiple
times to get multiple comment strings. `--no-comments' removes all
comments. It is a good idea to keep the length of a single comment
below 60 characters to avoid problems with mail programs wrapping
such lines. Note that comment lines, like all other header lines,
are not protected by the signature.

`--emit-version'
`--no-emit-version'
Force inclusion of the version string in ASCII armored output.
`--no-emit-version' disables this option.

`--sig-notation `name=value''
`--cert-notation `name=value''
`-N, --set-notation `name=value''
Put the name value pair into the signature as notation data.
`name' must consist only of printable characters or spaces, and
must contain a '@' character in the form keyname AT domain.com
(substituting the appropriate keyname and domain name, of course).
This is to help prevent pollution of the IETF reserved notation
namespace. The `--expert' flag overrides the '@' check. `value'
may be any printable string; it will be encoded in UTF8, so you
should check that your `--display-charset' is set correctly. If
you prefix `name' with an exclamation mark (!), the notation data
will be flagged as critical (rfc4880:5.2.3.16). `--sig-notation'
sets a notation for data signatures. `--cert-notation' sets a
notation for key signatures (certifications). `--set-notation'
sets both.

There are special codes that may be used in notation names. "%k"
will be expanded into the key ID of the key being signed, "%K"
into the long key ID of the key being signed, "%f" into the
fingerprint of the key being signed, "%s" into the key ID of the
key making the signature, "%S" into the long key ID of the key
making the signature, "%g" into the fingerprint of the key making
the signature (which might be a subkey), "%p" into the fingerprint
of the primary key of the key making the signature, "%c" into the
signature count from the OpenPGP smartcard, and "%%" results in a
single "%". %k, %K, and %f are only meaningful when making a key
signature (certification), and %c is only meaningful when using
the OpenPGP smartcard.

`--sig-policy-url `string''
`--cert-policy-url `string''
`--set-policy-url `string''
Use `string' as a Policy URL for signatures (rfc4880:5.2.3.20). If
you prefix it with an exclamation mark (!), the policy URL packet
will be flagged as critical. `--sig-policy-url' sets a policy url
for data signatures. `--cert-policy-url' sets a policy url for key
signatures (certifications). `--set-policy-url' sets both.

The same %-expandos used for notation data are available here as
well.

`--sig-keyserver-url `string''
Use `string' as a preferred keyserver URL for data signatures. If
you prefix it with an exclamation mark (!), the keyserver URL
packet will be flagged as critical.

The same %-expandos used for notation data are available here as
well.

`--set-filename `string''
Use `string' as the filename which is stored inside messages.
This overrides the default, which is to use the actual filename of
the file being encrypted.

`--for-your-eyes-only'
`--no-for-your-eyes-only'
Set the `for your eyes only' flag in the message. This causes
GnuPG to refuse to save the file unless the `--output' option is
given, and PGP to use a "secure viewer" with a claimed
Tempest-resistant font to display the message. This option
overrides `--set-filename'. `--no-for-your-eyes-only' disables
this option.

`--use-embedded-filename'
`--no-use-embedded-filename'
Try to create a file with a name as embedded in the data. This can
be a dangerous option as it allows to overwrite files. Defaults to
no.

`--cipher-algo `name''
Use `name' as cipher algorithm. Running the program with the
command `--version' yields a list of supported algorithms. If this
is not used the cipher algorithm is selected from the preferences
stored with the key. In general, you do not want to use this
option as it allows you to violate the OpenPGP standard.
`--personal-cipher-preferences' is the safe way to accomplish the
same thing.

`--digest-algo `name''
Use `name' as the message digest algorithm. Running the program
with the command `--version' yields a list of supported
algorithms. In general, you do not want to use this option as it
allows you to violate the OpenPGP standard.
`--personal-digest-preferences' is the safe way to accomplish the
same thing.

`--compress-algo `name''
Use compression algorithm `name'. "zlib" is RFC-1950 ZLIB
compression. "zip" is RFC-1951 ZIP compression which is used by
PGP. "bzip2" is a more modern compression scheme that can
compress some things better than zip or zlib, but at the cost of
more memory used during compression and decompression.
"uncompressed" or "none" disables compression. If this option is
not used, the default behavior is to examine the recipient key
preferences to see which algorithms the recipient supports. If all
else fails, ZIP is used for maximum compatibility.

ZLIB may give better compression results than ZIP, as the
compression window size is not limited to 8k. BZIP2 may give even
better compression results than that, but will use a significantly
larger amount of memory while compressing and decompressing. This
may be significant in low memory situations. Note, however, that
PGP (all versions) only supports ZIP compression. Using any
algorithm other than ZIP or "none" will make the message
unreadable with PGP. In general, you do not want to use this
option as it allows you to violate the OpenPGP standard.
`--personal-compress-preferences' is the safe way to accomplish
the same thing.

`--cert-digest-algo `name''
Use `name' as the message digest algorithm used when signing a
key. Running the program with the command `--version' yields a
list of supported algorithms. Be aware that if you choose an
algorithm that GnuPG supports but other OpenPGP implementations do
not, then some users will not be able to use the key signatures
you make, or quite possibly your entire key.

`--disable-cipher-algo `name''
Never allow the use of `name' as cipher algorithm. The given name
will not be checked so that a later loaded algorithm will still
get disabled.

`--disable-pubkey-algo `name''
Never allow the use of `name' as public key algorithm. The given
name will not be checked so that a later loaded algorithm will
still get disabled.

`--throw-keyids'
`--no-throw-keyids'
Do not put the recipient key IDs into encrypted messages. This
helps to hide the receivers of the message and is a limited
countermeasure against traffic analysis.(1) On the receiving
side, it may slow down the decryption process because all
available secret keys must be tried. `--no-throw-keyids' disables
this option. This option is essentially the same as using
`--hidden-recipient' for all recipients.

`--not-dash-escaped'
This option changes the behavior of cleartext signatures so that
they can be used for patch files. You should not send such an
armored file via email because all spaces and line endings are
hashed too. You can not use this option for data which has 5
dashes at the beginning of a line, patch files don't have this. A
special armor header line tells GnuPG about this cleartext
signature option.

`--escape-from-lines'
`--no-escape-from-lines'
Because some mailers change lines starting with "From " to ">From
" it is good to handle such lines in a special way when creating
cleartext signatures to prevent the mail system from breaking the
signature. Note that all other PGP versions do it this way too.
Enabled by default. `--no-escape-from-lines' disables this option.

`--passphrase-repeat `n''
Specify how many times `gpg2' will request a new passphrase be
repeated. This is useful for helping memorize a passphrase.
Defaults to 1 repetition.

`--passphrase-fd `n''
Read the passphrase from file descriptor `n'. Only the first line
will be read from file descriptor `n'. If you use 0 for `n', the
passphrase will be read from STDIN. This can only be used if only
one passphrase is supplied. Note that this passphrase is only
used if the option `--batch' has also been given. This is
different from `gpg'.

`--passphrase-file `file''
Read the passphrase from file `file'. Only the first line will be
read from file `file'. This can only be used if only one
passphrase is supplied. Obviously, a passphrase stored in a file is
of questionable security if other users can read this file. Don't
use this option if you can avoid it. Note that this passphrase is
only used if the option `--batch' has also been given. This is
different from `gpg'.

`--passphrase `string''
Use `string' as the passphrase. This can only be used if only one
passphrase is supplied. Obviously, this is of very questionable
security on a multi-user system. Don't use this option if you can
avoid it. Note that this passphrase is only used if the option
`--batch' has also been given. This is different from `gpg'.

`--command-fd `n''
This is a replacement for the deprecated shared-memory IPC mode.
If this option is enabled, user input on questions is not expected
from the TTY but from the given file descriptor. It should be used
together with `--status-fd'. See the file doc/DETAILS in the source
distribution for details on how to use it.

`--command-file `file''
Same as `--command-fd', except the commands are read out of file
`file'

`--allow-non-selfsigned-uid'
`--no-allow-non-selfsigned-uid'
Allow the import and use of keys with user IDs which are not
self-signed. This is not recommended, as a non self-signed user ID
is trivial to forge. `--no-allow-non-selfsigned-uid' disables.

`--allow-freeform-uid'
Disable all checks on the form of the user ID while generating a
new one. This option should only be used in very special
environments as it does not ensure the de-facto standard format of
user IDs.

`--ignore-time-conflict'
GnuPG normally checks that the timestamps associated with keys and
signatures have plausible values. However, sometimes a signature
seems to be older than the key due to clock problems. This option
makes these checks just a warning. See also `--ignore-valid-from'
for timestamp issues on subkeys.

`--ignore-valid-from'
GnuPG normally does not select and use subkeys created in the
future. This option allows the use of such keys and thus exhibits
the pre-1.0.7 behaviour. You should not use this option unless
there is some clock problem. See also `--ignore-time-conflict' for
timestamp issues with signatures.

`--ignore-crc-error'
The ASCII armor used by OpenPGP is protected by a CRC checksum
against transmission errors. Occasionally the CRC gets mangled
somewhere on the transmission channel but the actual content
(which is protected by the OpenPGP protocol anyway) is still okay.
This option allows GnuPG to ignore CRC errors.

`--ignore-mdc-error'
This option changes a MDC integrity protection failure into a
warning. This can be useful if a message is partially corrupt,
but it is necessary to get as much data as possible out of the
corrupt message. However, be aware that a MDC protection failure
may also mean that the message was tampered with intentionally by
an attacker.

`--no-default-keyring'
Do not add the default keyrings to the list of keyrings. Note that
GnuPG will not operate without any keyrings, so if you use this
option and do not provide alternate keyrings via `--keyring' or
`--secret-keyring', then GnuPG will still use the default public or
secret keyrings.

`--skip-verify'
Skip the signature verification step. This may be used to make the
decryption faster if the signature verification is not needed.

`--with-key-data'
Print key listings delimited by colons (like `--with-colons') and
print the public key data.

`--fast-list-mode'
Changes the output of the list commands to work faster; this is
achieved by leaving some parts empty. Some applications don't need
the user ID and the trust information given in the listings. By
using this options they can get a faster listing. The exact
behaviour of this option may change in future versions. If you
are missing some information, don't use this option.

`--no-literal'
This is not for normal use. Use the source to see for what it
might be useful.

`--set-filesize'
This is not for normal use. Use the source to see for what it
might be useful.

`--show-session-key'
Display the session key used for one message. See
`--override-session-key' for the counterpart of this option.

We think that Key Escrow is a Bad Thing; however the user should
have the freedom to decide whether to go to prison or to reveal
the content of one specific message without compromising all
messages ever encrypted for one secret key. DON'T USE IT UNLESS
YOU ARE REALLY FORCED TO DO SO.

`--override-session-key `string''
Don't use the public key but the session key `string'. The format
of this string is the same as the one printed by
`--show-session-key'. This option is normally not used but comes
handy in case someone forces you to reveal the content of an
encrypted message; using this option you can do this without
handing out the secret key.

`--ask-sig-expire'
`--no-ask-sig-expire'
When making a data signature, prompt for an expiration time. If
this option is not specified, the expiration time set via
`--default-sig-expire' is used. `--no-ask-sig-expire' disables
this option.

`--default-sig-expire'
The default expiration time to use for signature expiration. Valid
values are "0" for no expiration, a number followed by the letter d
(for days), w (for weeks), m (for months), or y (for years) (for
example "2m" for two months, or "5y" for five years), or an
absolute date in the form YYYY-MM-DD. Defaults to "0".

`--ask-cert-expire'
`--no-ask-cert-expire'
When making a key signature, prompt for an expiration time. If this
option is not specified, the expiration time set via
`--default-cert-expire' is used. `--no-ask-cert-expire' disables
this option.

`--default-cert-expire'
The default expiration time to use for key signature expiration.
Valid values are "0" for no expiration, a number followed by the
letter d (for days), w (for weeks), m (for months), or y (for
years) (for example "2m" for two months, or "5y" for five years),
or an absolute date in the form YYYY-MM-DD. Defaults to "0".

`--allow-secret-key-import'
This is an obsolete option and is not used anywhere.

`--allow-multiple-messages'

`--no-allow-multiple-messages'
Allow processing of multiple OpenPGP messages contained in a
single file or stream. Some programs that call GPG are not
prepared to deal with multiple messages being processed together,
so this option defaults to no. Note that versions of GPG prior to
1.4.7 always allowed multiple messages.

Warning: Do not use this option unless you need it as a temporary
workaround!

`--enable-special-filenames'
This options enables a mode in which filenames of the form `-&n',
where n is a non-negative decimal number, refer to the file
descriptor n and not to a file with that name.

`--no-expensive-trust-checks'
Experimental use only.

`--preserve-permissions'
Don't change the permissions of a secret keyring back to user
read/write only. Use this option only if you really know what you
are doing.

`--default-preference-list `string''
Set the list of default preferences to `string'. This preference
list is used for new keys and becomes the default for "setpref" in
the edit menu.

`--default-keyserver-url `name''
Set the default keyserver URL to `name'. This keyserver will be
used as the keyserver URL when writing a new self-signature on a
key, which includes key generation and changing preferences.

`--list-config'
Display various internal configuration parameters of GnuPG. This
option is intended for external programs that call GnuPG to
perform tasks, and is thus not generally useful. See the file
`doc/DETAILS' in the source distribution for the details of which
configuration items may be listed. `--list-config' is only usable
with `--with-colons' set.

`--gpgconf-list'
This command is similar to `--list-config' but in general only
internally used by the `gpgconf' tool.

`--gpgconf-test'
This is more or less dummy action. However it parses the
configuration file and returns with failure if the configuration
file would prevent `gpg' from startup. Thus it may be used to run
a syntax check on the configuration file.

---------- Footnotes ----------

(1) Using a little social engineering anyone who is able to decrypt
the message can check whether one of the other recipients is the one he
suspects.

File: gnupg.info, Node: Deprecated Options, Prev: GPG Esoteric Options, Up: GPG Options

3.2.7 Deprecated options
------------------------

`--show-photos'
`--no-show-photos'
Causes `--list-keys', `--list-sigs', `--list-public-keys',
`--list-secret-keys', and verifying a signature to also display
the photo ID attached to the key, if any. See also
`--photo-viewer'. These options are deprecated. Use
`--list-options [no-]show-photos' and/or `--verify-options
[no-]show-photos' instead.

`--show-keyring'
Display the keyring name at the head of key listings to show which
keyring a given key resides on. This option is deprecated: use
`--list-options [no-]show-keyring' instead.

`--always-trust'
Identical to `--trust-model always'. This option is deprecated.

`--show-notation'
`--no-show-notation'
Show signature notations in the `--list-sigs' or `--check-sigs'
listings as well as when verifying a signature with a notation in
it. These options are deprecated. Use `--list-options
[no-]show-notation' and/or `--verify-options [no-]show-notation'
instead.

`--show-policy-url'
`--no-show-policy-url'
Show policy URLs in the `--list-sigs' or `--check-sigs' listings
as well as when verifying a signature with a policy URL in it.
These options are deprecated. Use `--list-options
[no-]show-policy-url' and/or `--verify-options
[no-]show-policy-url' instead.

File: gnupg.info, Node: GPG Configuration, Next: GPG Examples, Prev: GPG Options, Up: Invoking GPG

3.3 Configuration files
=======================

There are a few configuration files to control certain aspects of
`gpg2''s operation. Unless noted, they are expected in the current home
directory (*note option --homedir::).

`gpg.conf'
This is the standard configuration file read by `gpg2' on
startup. It may contain any valid long option; the leading two
dashes may not be entered and the option may not be abbreviated.
This default name may be changed on the command line (*note
gpg-option --options::). You should backup this file.

Note that on larger installations, it is useful to put predefined
files into the directory `/etc/skel/.gnupg/' so that newly created users
start up with a working configuration. For existing users the a small
helper script is provided to create these files (*note addgnupghome::).

For internal purposes `gpg2' creates and maintains a few other
files; They all live in in the current home directory (*note option
--homedir::). Only the `gpg2' may modify these files.

`~/.gnupg/secring.gpg'
The secret keyring. You should backup this file.

`~/.gnupg/secring.gpg.lock'
The lock file for the secret keyring.

`~/.gnupg/pubring.gpg'
The public keyring. You should backup this file.

`~/.gnupg/pubring.gpg.lock'
The lock file for the public keyring.

`~/.gnupg/trustdb.gpg'
The trust database. There is no need to backup this file; it is
better to backup the ownertrust values (*note option
--export-ownertrust::).

`~/.gnupg/trustdb.gpg.lock'
The lock file for the trust database.

`~/.gnupg/random_seed'
A file used to preserve the state of the internal random pool.

`/usr[/local]/share/gnupg/options.skel'
The skeleton options file.

`/usr[/local]/lib/gnupg/'
Default location for extensions.

Operation is further controlled by a few environment variables:

HOME
Used to locate the default home directory.

GNUPGHOME
If set directory used instead of "~/.gnupg".

GPG_AGENT_INFO
Used to locate the gpg-agent. The value consists of 3 colon
delimited fields: The first is the path to the Unix Domain
Socket, the second the PID of the gpg-agent and the protocol
version which should be set to 1. When starting the gpg-agent as
described in its documentation, this variable is set to the correct
value. The option `--gpg-agent-info' can be used to override it.

PINENTRY_USER_DATA
This value is passed via gpg-agent to pinentry. It is useful to
convey extra information to a custom pinentry.

COLUMNS
LINES
Used to size some displays to the full size of the screen.

LANGUAGE
Apart from its use by GNU, it is used in the W32 version to
override the language selection done through the Registry. If
used and set to a valid and available language name (LANGID),
the file with the translation is loaded from

`GPGDIR/gnupg.nls/LANGID.mo'. Here GPGDIR is the directory out
of which the gpg binary has been loaded. If it can't be loaded
the Registry is tried and as last resort the native Windows
locale system is used.

File: gnupg.info, Node: GPG Examples, Next: Unattended Usage of GPG, Prev: GPG Configuration, Up: Invoking GPG

3.4 Examples
============

gpg -se -r `Bob' `file'
sign and encrypt for user Bob

gpg -clearsign `file'
make a clear text signature

gpg -sb `file'
make a detached signature

gpg -u 0x12345678 -sb `file'
make a detached signature with the key 0x12345678

gpg -list-keys `user_ID'
show keys

gpg -fingerprint `user_ID'
show fingerprint

gpg -verify `pgpfile'
gpg -verify `sigfile'
Verify the signature of the file but do not output the data. The
second form is used for detached signatures, where `sigfile' is
the detached signature (either ASCII armored or binary) and are
the signed data; if this is not given, the name of the file
holding the signed data is constructed by cutting off the
extension (".asc" or ".sig") of `sigfile' or by asking the user
for the filename.

RETURN VALUE
************

The program returns 0 if everything was fine, 1 if at least a signature
was bad, and other error codes for fatal errors.

WARNINGS
********

Use a *good* password for your user account and a *good* passphrase to
protect your secret key. This passphrase is the weakest part of the
whole system. Programs to do dictionary attacks on your secret keyring
are very easy to write and so you should protect your "~/.gnupg/"
directory very well.

Keep in mind that, if this program is used over a network (telnet),
it is *very* easy to spy out your passphrase!

If you are going to verify detached signatures, make sure that the
program knows about it; either give both filenames on the command line
or use `-' to specify STDIN.

INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS
********************************************

GnuPG tries to be a very flexible implementation of the OpenPGP
standard. In particular, GnuPG implements many of the optional parts of
the standard, such as the SHA-512 hash, and the ZLIB and BZIP2
compression algorithms. It is important to be aware that not all
OpenPGP programs implement these optional algorithms and that by
forcing their use via the `--cipher-algo', `--digest-algo',
`--cert-digest-algo', or `--compress-algo' options in GnuPG, it is
possible to create a perfectly valid OpenPGP message, but one that
cannot be read by the intended recipient.

There are dozens of variations of OpenPGP programs available, and
each supports a slightly different subset of these optional algorithms.
For example, until recently, no (unhacked) version of PGP supported the
BLOWFISH cipher algorithm. A message using BLOWFISH simply could not be
read by a PGP user. By default, GnuPG uses the standard OpenPGP
preferences system that will always do the right thing and create
messages that are usable by all recipients, regardless of which OpenPGP
program they use. Only override this safe default if you really know
what you are doing.

If you absolutely must override the safe default, or if the
preferences on a given key are invalid for some reason, you are far
better off using the `--pgp6', `--pgp7', or `--pgp8' options. These
options are safe as they do not force any particular algorithms in
violation of OpenPGP, but rather reduce the available algorithms to a
"PGP-safe" list.

BUGS
****

On older systems this program should be installed as setuid(root). This
is necessary to lock memory pages. Locking memory pages prevents the
operating system from writing memory pages (which may contain
passphrases or other sensitive material) to disk. If you get no warning
message about insecure memory your operating system supports locking
without being root. The program drops root privileges as soon as locked
memory is allocated.

Note also that some systems (especially laptops) have the ability to
"suspend to disk" (also known as "safe sleep" or "hibernate"). This
writes all memory to disk before going into a low power or even powered
off mode. Unless measures are taken in the operating system to protect
the saved memory, passphrases or other sensitive material may be
recoverable from it later.

Before you report a bug you should first search the mailing list
archives for similar problems and second check whether such a bug has
already been reported to our bug tracker at http://bugs.gnupg.org .

File: gnupg.info, Node: Unattended Usage of GPG, Prev: GPG Examples, Up: Invoking GPG

3.5 Unattended Usage
====================

`gpg' is often used as a backend engine by other software. To help
with this a machine interface has been defined to have an unambiguous
way to do this. The options `--status-fd' and `--batch' are almost
always required for this.

* Menu:

* Unattended GPG key generation:: Unattended key generation

File: gnupg.info, Node: Unattended GPG key generation, Up: Unattended Usage of GPG

3.5.1 Unattended key generation
-------------------------------

The command `--gen-key' may be used along with the option `--batch' for
unattended key generation. The parameters are either read from stdin
or given as a file on the command line. The format of the parameter
file is as follows:

* Text only, line length is limited to about 1000 characters.

* UTF-8 encoding must be used to specify non-ASCII characters.

* Empty lines are ignored.

* Leading and trailing while space is ignored.

* A hash sign as the first non white space character indicates a
comment line.

* Control statements are indicated by a leading percent sign, the
arguments are separated by white space from the keyword.

* Parameters are specified by a keyword, followed by a colon.
Arguments are separated by white space.

* The first parameter must be `Key-Type'; control statements may be
placed anywhere.

* The order of the parameters does not matter except for `Key-Type'
which must be the first parameter. The parameters are only used
for the generated keyblock (primary and subkeys); parameters
from previous sets are not used. Some syntactically checks may
be performed.

* Key generation takes place when either the end of the parameter
file is reached, the next `Key-Type' parameter is encountered or
at the control statement `%commit' is encountered.

Control statements:

%echo TEXT
Print TEXT as diagnostic.

%dry-run
Suppress actual key generation (useful for syntax checking).

%commit
Perform the key generation. Note that an implicit commit is done
at the next Key-Type parameter.

%pubring FILENAME
%secring FILENAME
Do not write the key to the default or commandline given keyring
but to FILENAME. This must be given before the first commit to
take place, duplicate specification of the same filename is
ignored, the last filename before a commit is used. The filename
is used until a new filename is used (at commit points) and all
keys are written to that file. If a new filename is given, this
file is created (and overwrites an existing one). For GnuPG
versions prior to 2.1, both control statements must be given. For
GnuPG 2.1 and later `%secring' is a no-op.

%ask-passphrase
%no-ask-passphrase
Enable (or disable) a mode where the command `passphrase' is
ignored and instead the usual passphrase dialog is used. This does
not make sense for batch key generation; however the unattended key
generation feature is also used by GUIs and this feature
relinquishes the GUI from implementing its own passphrase entry
code. These are global control statements and affect all future
key genrations.

%no-protection
Since GnuPG version 2.1 it is not anymore possible to specify a
passphrase for unattended key generation. The passphrase command
is simply ignored and `%ask-passpharse' is thus implicitly enabled.
Using this option allows the creation of keys without any
passphrase protection. This option is mainly intended for
regression tests.

%transient-key
If given the keys are created using a faster and a somewhat less
secure random number generator. This option may be used for keys
which are only used for a short time and do not require full
cryptographic strength. It takes only effect if used together with
the control statement `%no-protection'.

General Parameters:

Key-Type: ALGO
Starts a new parameter block by giving the type of the primary
key. The algorithm must be capable of signing. This is a required
parameter. ALGO may either be an OpenPGP algorithm number or a
string with the algorithm name. The special value `default' may
be used for ALGO to create the default key type; in this case a
`Key-Usage' shall not be given and `default' also be used for
`Subkey-Type'.

Key-Length: NBITS
The requested length of the generated key in bits. The default is
returned by running the command `gpg2 --gpgconf-list'.

Key-Grip: HEXSTRING
This is optional and used to generate a CSR or certificate for an
already existing key. Key-Length will be ignored when given.

Key-Usage: USAGE-LIST
Space or comma delimited list of key usages. Allowed values are
`encrypt', `sign', and `auth'. This is used to generate the key
flags. Please make sure that the algorithm is capable of this
usage. Note that OpenPGP requires that all primary keys are
capable of certification, so no matter what usage is given here,
the `cert' flag will be on. If no `Key-Usage' is specified and
the `Key-Type' is not `default', all allowed usages for that
particular algorithm are used; if it is not given but `default' is
used the usage will be `sign'.

Subkey-Type: ALGO
This generates a secondary key (subkey). Currently only one subkey
can be handled. See also `Key-Type' above.

Subkey-Length: NBITS
Length of the secondary key (subkey) in bits. The default is
returned by running the command `gpg2 --gpgconf-list'".

Subkey-Usage: USAGE-LIST
Key usage lists for a subkey; similar to `Key-Usage'.

Passphrase: STRING
If you want to specify a passphrase for the secret key, enter it
here. Default is not to use any passphrase.

Name-Real: NAME
Name-Comment: COMMENT
Name-Email: EMAIL
The three parts of a user name. Remember to use UTF-8 encoding
here. If you don't give any of them, no user ID is created.

Expire-Date: ISO-DATE|(NUMBER[d|w|m|y])
Set the expiration date for the key (and the subkey). It may
either be entered in ISO date format (e.g. "20000815T145012") or
as number of days, weeks, month or years after the creation date.
The special notation "seconds=N" is also allowed to specify a
number of seconds since creation. Without a letter days are
assumed. Note that there is no check done on the overflow of the
type used by OpenPGP for timestamps. Thus you better make sure
that the given value make sense. Although OpenPGP works with time
intervals, GnuPG uses an absolute value internally and thus the
last year we can represent is 2105.

Ceation-Date: ISO-DATE
Set the creation date of the key as stored in the key information
and which is also part of the fingerprint calculation. Either a
date like "1986-04-26" or a full timestamp like "19860426T042640"
may be used. The time is considered to be UTC. The special
notation "seconds=N" may be used to directly specify a the number
of seconds since Epoch (Unix time). If it is not given the
current time is used.

Preferences: STRING
Set the cipher, hash, and compression preference values for this
key. This expects the same type of string as the sub-command
`setpref' in the `--edit-key' menu.

Revoker: ALGO:FPR [sensitive]
Add a designated revoker to the generated key. Algo is the public
key algorithm of the designated revoker (i.e. RSA=1, DSA=17, etc.)
FPR is the fingerprint of the designated revoker. The optional
`sensitive' flag marks the designated revoker as sensitive
information. Only v4 keys may be designated revokers.

Keyserver: STRING
This is an optional parameter that specifies the preferred
keyserver URL for the key.

Handle: STRING
This is an optional parameter only used with the status lines
KEY_CREATED and KEY_NOT_CREATED. STRING may be up to 100
characters and should not contain spaces. It is useful for batch
key generation to associate a key parameter block with a status
line.

Here is an example on how to create a key:
$ cat >foo <<EOF
%echo Generating a basic OpenPGP key
Key-Type: DSA
Key-Length: 1024
Subkey-Type: ELG-E
Subkey-Length: 1024
Name-Real: Joe Tester
Name-Comment: with stupid passphrase
Name-Email: joe AT foo.bar
Expire-Date: 0
Passphrase: abc
%pubring foo.pub
%secring foo.sec
# Do a commit here, so that we can later print "done" :-)
%commit
%echo done
EOF
$ gpg2 --batch --gen-key foo
[...]
$ gpg2 --no-default-keyring --secret-keyring ./foo.sec \
--keyring ./foo.pub --list-secret-keys
/home/wk/work/gnupg-stable/scratch/foo.sec
------------------------------------------
sec 1024D/915A878D 2000-03-09 Joe Tester (with stupid passphrase) <joe AT foo.bar>
ssb 1024g/8F70E2C0 2000-03-09

If you want to create a key with the default algorithms you would use
these parameters:
%echo Generating a default key
Key-Type: default
Subkey-Type: default
Name-Real: Joe Tester
Name-Comment: with stupid passphrase
Name-Email: joe AT foo.bar
Expire-Date: 0
Passphrase: abc
%pubring foo.pub
%secring foo.sec
# Do a commit here, so that we can later print "done" :-)
%commit
%echo done

File: gnupg.info, Node: Invoking GPGSM, Next: Invoking SCDAEMON, Prev: Invoking GPG, Up: Top

4 Invoking GPGSM
****************

`gpgsm' is a tool similar to `gpg' to provide digital encryption and
signing services on X.509 certificates and the CMS protocol. It is
mainly used as a backend for S/MIME mail processing. `gpgsm' includes
a full featured certificate management and complies with all rules
defined for the German Sphinx project.

*Note Option Index::, for an index to `GPGSM''s commands and options.

* Menu:

* GPGSM Commands:: List of all commands.
* GPGSM Options:: List of all options.
* GPGSM Configuration:: Configuration files.
* GPGSM Examples:: Some usage examples.

Developer information:
* Unattended Usage:: Using `gpgsm' from other programs.
* GPGSM Protocol:: The protocol the server mode uses.

File: gnupg.info, Node: GPGSM Commands, Next: GPGSM Options, Up: Invoking GPGSM

4.1 Commands
============

Commands are not distinguished from options except for the fact that
only one command is allowed.

* Menu:

* General GPGSM Commands:: Commands not specific to the functionality.
* Operational GPGSM Commands:: Commands to select the type of operation.
* Certificate Management:: How to manage certificates.

File: gnupg.info, Node: General GPGSM Commands, Next: Operational GPGSM Commands, Up: GPGSM Commands

4.1.1 Commands not specific to the function
-------------------------------------------

`--version'
Print the program version and licensing information. Note that you
cannot abbreviate this command.

`--help, -h'
Print a usage message summarizing the most useful command-line
options. Note that you cannot abbreviate this command.

`--warranty'
Print warranty information. Note that you cannot abbreviate this
command.

`--dump-options'
Print a list of all available options and commands. Note that you
cannot abbreviate this command.

File: gnupg.info, Node: Operational GPGSM Commands, Next: Certificate Management, Prev: General GPGSM Commands, Up: GPGSM Commands

4.1.2 Commands to select the type of operation
----------------------------------------------

`--encrypt'
Perform an encryption. The keys the data is encrypted too must be
set using the option `--recipient'.

`--decrypt'
Perform a decryption; the type of input is automatically
determined. It may either be in binary form or PEM encoded;
automatic determination of base-64 encoding is not done.

`--sign'
Create a digital signature. The key used is either the fist one
found in the keybox or those set with the `--local-user' option.

`--verify'
Check a signature file for validity. Depending on the arguments a
detached signature may also be checked.

`--server'
Run in server mode and wait for commands on the `stdin'.

`--call-dirmngr COMMAND [ARGS]'
Behave as a Dirmngr client issuing the request COMMAND with the
optional list of ARGS. The output of the Dirmngr is printed
stdout. Please note that file names given as arguments should
have an absolute file name (i.e. commencing with `/' because they
are passed verbatim to the Dirmngr and the working directory of the
Dirmngr might not be the same as the one of this client.
Currently it is not possible to pass data via stdin to the
Dirmngr. COMMAND should not contain spaces.

This is command is required for certain maintaining tasks of the
dirmngr where a dirmngr must be able to call back to `gpgsm'. See
the Dirmngr manual for details.

`--call-protect-tool ARGUMENTS'
Certain maintenance operations are done by an external program call
`gpg-protect-tool'; this is usually not installed in a directory
listed in the PATH variable. This command provides a simple
wrapper to access this tool. ARGUMENTS are passed verbatim to
this command; use `--help' to get a list of supported operations.

File: gnupg.info, Node: Certificate Management, Prev: Operational GPGSM Commands, Up: GPGSM Commands

4.1.3 How to manage the certificates and keys
---------------------------------------------

`--gen-key'
-This command allows the creation of a certificate signing
request. It -is commonly used along with the `--output' option to
save the -created CSR into a file. If used with the `--batch' a
parameter -file is used to create the CSR.

`--list-keys'
`-k'
List all available certificates stored in the local key database.
Note that the displayed data might be reformatted for better human
readability and illegal characters are replaced by safe
substitutes.

`--list-secret-keys'
`-K'
List all available certificates for which a corresponding a secret
key is available.

`--list-external-keys PATTERN'
List certificates matching PATTERN using an external server. This
utilizes the `dirmngr' service.

`--list-chain'
Same as `--list-keys' but also prints all keys making up the chain.

`--dump-cert'
`--dump-keys'
List all available certificates stored in the local key database
using a format useful mainly for debugging.

`--dump-chain'
Same as `--dump-keys' but also prints all keys making up the chain.

`--dump-secret-keys'
List all available certificates for which a corresponding a secret
key is available using a format useful mainly for debugging.

`--dump-external-keys PATTERN'
List certificates matching PATTERN using an external server. This
utilizes the `dirmngr' service. It uses a format useful mainly
for debugging.

`--keydb-clear-some-cert-flags'
This is a debugging aid to reset certain flags in the key database
which are used to cache certain certificate stati. It is
especially useful if a bad CRL or a weird running OCSP responder
did accidentally revoke certificate. There is no security issue
with this command because `gpgsm' always make sure that the
validity of a certificate is checked right before it is used.

`--delete-keys PATTERN'
Delete the keys matching PATTERN. Note that there is no command
to delete the secret part of the key directly. In case you need
to do this, you should run the command `gpgsm --dump-secret-keys
KEYID' before you delete the key, copy the string of hex-digits in
the "keygrip" line and delete the file consisting of these
hex-digits and the suffix `.key' from the `private-keys-v1.d'
directory below our GnuPG home directory (usually `~/.gnupg').

`--export [PATTERN]'
Export all certificates stored in the Keybox or those specified by
the optional PATTERN. Those pattern consist of a list of user ids
(*note how-to-specify-a-user-id::). When used along with the
`--armor' option a few informational lines are prepended before
each block. There is one limitation: As there is no commonly
agreed upon way to pack more than one certificate into an ASN.1
structure, the binary export (i.e. without using `armor') works
only for the export of one certificate. Thus it is required to
specify a PATTERN which yields exactly one certificate. Ephemeral
certificate are only exported if all PATTERN are given as
fingerprints or keygrips.

`--export-secret-key-p12 KEY-ID'
Export the private key and the certificate identified by KEY-ID in
a PKCS#12 format. When using along with the `--armor' option a few
informational lines are prepended to the output. Note, that the
PKCS#12 format is not very secure and this command is only
provided if there is no other way to exchange the private key.
(*note option --p12-charset::)

`--import [FILES]'
Import the certificates from the PEM or binary encoded files as
well as from signed-only messages. This command may also be used
to import a secret key from a PKCS#12 file.

`--learn-card'
Read information about the private keys from the smartcard and
import the certificates from there. This command utilizes the
`gpg-agent' and in turn the `scdaemon'.

`--passwd USER_ID'
Change the passphrase of the private key belonging to the
certificate specified as USER_ID. Note, that changing the
passphrase/PIN of a smartcard is not yet supported.

File: gnupg.info, Node: GPGSM Options, Next: GPGSM Configuration, Prev: GPGSM Commands, Up: Invoking GPGSM

4.2 Option Summary
==================

`GPGSM' features a bunch of options to control the exact behaviour and
to change the default configuration.

* Menu:

* Configuration Options:: How to change the configuration.
* Certificate Options:: Certificate related options.
* Input and Output:: Input and Output.
* CMS Options:: How to change how the CMS is created.
* Esoteric Options:: Doing things one usually do not want to do.

File: gnupg.info, Node: Configuration Options, Next: Certificate Options, Up: GPGSM Options

4.2.1 How to change the configuration
-------------------------------------

These options are used to change the configuration and are usually found
in the option file.

`--options FILE'
Reads configuration from FILE instead of from the default per-user
configuration file. The default configuration file is named
`gpgsm.conf' and expected in the `.gnupg' directory directly below
the home directory of the user.

`-v'

`--verbose'
Outputs additional information while running. You can increase
the verbosity by giving several verbose commands to `gpgsm', such
as `-vv'.

`--policy-file FILENAME'
Change the default name of the policy file to FILENAME.

`--agent-program FILE'
Specify an agent program to be used for secret key operations. The
default value is the `/usr/local/bin/gpg-agent'. This is only used
as a fallback when the environment variable `GPG_AGENT_INFO' is not
set or a running agent cannot be connected.

`--dirmngr-program FILE'
Specify a dirmngr program to be used for CRL checks. The default
value is `/usr/sbin/dirmngr'. This is only used as a fallback
when the environment variable `DIRMNGR_INFO' is not set or a
running dirmngr cannot be connected.

`--prefer-system-dirmngr'
If a system wide `dirmngr' is running in daemon mode, first try to
connect to this one. Fallback to a pipe based server if this does
not work. Under Windows this option is ignored because the system
dirmngr is always used.

`--disable-dirmngr'
Entirely disable the use of the Dirmngr.

`--no-secmem-warning'
Do not print a warning when the so called "secure memory" cannot
be used.

`--log-file FILE'
When running in server mode, append all logging output to FILE.

File: gnupg.info, Node: Certificate Options, Next: Input and Output, Prev: Configuration Options, Up: GPGSM Options

4.2.2 Certificate related options
---------------------------------

`--enable-policy-checks'
`--disable-policy-checks'
By default policy checks are enabled. These options may be used to
change it.

`--enable-crl-checks'
`--disable-crl-checks'
By default the CRL checks are enabled and the DirMngr is used to
check for revoked certificates. The disable option is most useful
with an off-line network connection to suppress this check.

`--enable-trusted-cert-crl-check'
`--disable-trusted-cert-crl-check'
By default the CRL for trusted root certificates are checked like
for any other certificates. This allows a CA to revoke its own
certificates voluntary without the need of putting all ever issued
certificates into a CRL. The disable option may be used to switch
this extra check off. Due to the caching done by the Dirmngr,
there will not be any noticeable performance gain. Note, that
this also disables possible OCSP checks for trusted root
certificates. A more specific way of disabling this check is by
adding the "relax" keyword to the root CA line of the
`trustlist.txt'

`--force-crl-refresh'
Tell the dirmngr to reload the CRL for each request. For better
performance, the dirmngr will actually optimize this by suppressing
the loading for short time intervals (e.g. 30 minutes). This option
is useful to make sure that a fresh CRL is available for
certificates hold in the keybox. The suggested way of doing this
is by using it along with the option `--with-validation' for a key
listing command. This option should not be used in a
configuration file.

`--enable-ocsp'
`--disable-ocsp'
By default OCSP checks are disabled. The enable option may be
used to enable OCSP checks via Dirmngr. If CRL checks are also
enabled, CRLs will be used as a fallback if for some reason an
OCSP request will not succeed. Note, that you have to allow OCSP
requests in Dirmngr's configuration too (option `--allow-ocsp')
and configure Dirmngr properly. If you do not do so you will get
the error code `Not supported'.

`--auto-issuer-key-retrieve'
If a required certificate is missing while validating the chain of
certificates, try to load that certificate from an external
location. This usually means that Dirmngr is employed to search
for the certificate. Note that this option makes a "web bug" like
behavior possible. LDAP server operators can see which keys you
request, so by sending you a message signed by a brand new key
(which you naturally will not have on your local keybox), the
operator can tell both your IP address and the time when you
verified the signature.

`--validation-model NAME'
This option changes the default validation model. The only
possible values are "shell" (which is the default), "chain" which
forces the use of the chain model and "steed" for a new simplified
model. The chain model is also used if an option in the
`trustlist.txt' or an attribute of the certificate requests it.
However the standard model (shell) is in that case always tried
first.

`--ignore-cert-extension OID'
Add OID to the list of ignored certificate extensions. The OID is
expected to be in dotted decimal form, like `2.5.29.3'. This
option may be used more than once. Critical flagged certificate
extensions matching one of the OIDs in the list are treated as if
they are actually handled and thus the certificate will not be
rejected due to an unknown critical extension. Use this option
with care because extensions are usually flagged as critical for a
reason.

File: gnupg.info, Node: Input and Output, Next: CMS Options, Prev: Certificate Options, Up: GPGSM Options

4.2.3 Input and Output
----------------------

`--armor'
`-a'
Create PEM encoded output. Default is binary output.

`--base64'
Create Base-64 encoded output; i.e. PEM without the header lines.

`--assume-armor'
Assume the input data is PEM encoded. Default is to autodetect the
encoding but this is may fail.

`--assume-base64'
Assume the input data is plain base-64 encoded.

`--assume-binary'
Assume the input data is binary encoded.

`--p12-charset NAME'
`gpgsm' uses the UTF-8 encoding when encoding passphrases for
PKCS#12 files. This option may be used to force the passphrase to
be encoded in the specified encoding NAME. This is useful if the
application used to import the key uses a different encoding and
thus will not be able to import a file generated by `gpgsm'.
Commonly used values for NAME are `Latin1' and `CP850'. Note that
`gpgsm' itself automagically imports any file with a passphrase
encoded to the most commonly used encodings.

`--default-key USER_ID'
Use USER_ID as the standard key for signing. This key is used if
no other key has been defined as a signing key. Note, that the
first `--local-users' option also sets this key if it has not yet
been set; however `--default-key' always overrides this.

`--local-user USER_ID'

`-u USER_ID'
Set the user(s) to be used for signing. The default is the first
secret key found in the database.

`--recipient NAME'
`-r'
Encrypt to the user id NAME. There are several ways a user id may
be given (*note how-to-specify-a-user-id::).

`--output FILE'
`-o FILE'
Write output to FILE. The default is to write it to stdout.

`--with-key-data'
Displays extra information with the `--list-keys' commands.
Especially a line tagged `grp' is printed which tells you the
keygrip of a key. This string is for example used as the file
name of the secret key.

`--with-validation'
When doing a key listing, do a full validation check for each key
and print the result. This is usually a slow operation because it
requires a CRL lookup and other operations.

When used along with -import, a validation of the certificate to
import is done and only imported if it succeeds the test. Note
that this does not affect an already available certificate in the
DB. This option is therefore useful to simply verify a
certificate.

`--with-md5-fingerprint'
For standard key listings, also print the MD5 fingerprint of the
certificate.

`--with-keygrip'
Include the keygrip in standard key listings. Note that the
keygrip is always listed in -with-colons mode.

File: gnupg.info, Node: CMS Options, Next: Esoteric Options, Prev: Input and Output, Up: GPGSM Options

4.2.4 How to change how the CMS is created.
-------------------------------------------

`--include-certs N'
Using N of -2 includes all certificate except for the root cert,
-1 includes all certs, 0 does not include any certs, 1 includes
only the signers cert and all other positive values include up to N
certificates starting with the signer cert. The default is -2.

`--cipher-algo OID'
Use the cipher algorithm with the ASN.1 object identifier OID for
encryption. For convenience the strings `3DES', `AES' and
`AES256' may be used instead of their OIDs. The default is `3DES'
(1.2.840.113549.3.7).

`--digest-algo `name''
Use `name' as the message digest algorithm. Usually this
algorithm is deduced from the respective signing certificate. This
option forces the use of the given algorithm and may lead to severe
interoperability problems.

File: gnupg.info, Node: Esoteric Options, Prev: CMS Options, Up: GPGSM Options

4.2.5 Doing things one usually do not want to do.
-------------------------------------------------

`--extra-digest-algo NAME'
Sometimes signatures are broken in that they announce a different
digest algorithm than actually used. `gpgsm' uses a one-pass data
processing model and thus needs to rely on the announced digest
algorithms to properly hash the data. As a workaround this option
may be used to tell gpg to also hash the data using the algorithm
NAME; this slows processing down a little bit but allows to verify
such broken signatures. If `gpgsm' prints an error like "digest
algo 8 has not been enabled" you may want to try this option, with
`SHA256' for NAME.

`--with-ephemeral-keys'
Include ephemeral flagged keys in the output of key listings. Note
that they are included anyway if the key specification for a
listing is given as fingerprint or keygrip.

`--debug-level LEVEL'
Select the debug level for investigating problems. LEVEL may be a
numeric value or by a keyword:

`none'
No debugging at all. A value of less than 1 may be used
instead of the keyword.

`basic'
Some basic debug messages. A value between 1 and 2 may be
used instead of the keyword.

`advanced'
More verbose debug messages. A value between 3 and 5 may be
used instead of the keyword.

`expert'
Even more detailed messages. A value between 6 and 8 may be
used instead of the keyword.

`guru'
All of the debug messages you can get. A value greater than 8
may be used instead of the keyword. The creation of hash
tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They
are however carefully selected to best aid in debugging.

`--debug FLAGS'
This option is only useful for debugging and the behaviour may
change at any time without notice; using `--debug-levels' is the
preferred method to select the debug verbosity. FLAGS are bit
encoded and may be given in usual C-Syntax. The currently defined
bits are:

`0 (1)'
X.509 or OpenPGP protocol related data

`1 (2)'
values of big number integers

`2 (4)'
low level crypto operations

`5 (32)'
memory allocation

`6 (64)'
caching

`7 (128)'
show memory statistics.

`9 (512)'
write hashed data to files named `dbgmd-000*'

`10 (1024)'
trace Assuan protocol

Note, that all flags set using this option may get overridden by
`--debug-level'.

`--debug-all'
Same as `--debug=0xffffffff'

`--debug-allow-core-dump'
Usually `gpgsm' tries to avoid dumping core by well written code
and by disabling core dumps for security reasons. However, bugs
are pretty durable beasts and to squash them it is sometimes
useful to have a core dump. This option enables core dumps unless
the Bad Thing happened before the option parsing.

`--debug-no-chain-validation'
This is actually not a debugging option but only useful as such.
It lets `gpgsm' bypass all certificate chain validation checks.

`--debug-ignore-expiration'
This is actually not a debugging option but only useful as such.
It lets `gpgsm' ignore all notAfter dates, this is used by the
regression tests.

`--fixed-passphrase STRING'
Supply the passphrase STRING to the gpg-protect-tool. This option
is only useful for the regression tests included with this package
and may be revised or removed at any time without notice.

`--no-common-certs-import'
Suppress the import of common certificates on keybox creation.

All the long options may also be given in the configuration file
after stripping off the two leading dashes.

File: gnupg.info, Node: GPGSM Configuration, Next: GPGSM Examples, Prev: GPGSM Options, Up: Invoking GPGSM

4.3 Configuration files
=======================

There are a few configuration files to control certain aspects of
`gpgsm''s operation. Unless noted, they are expected in the current
home directory (*note option --homedir::).

`gpgsm.conf'
This is the standard configuration file read by `gpgsm' on
startup. It may contain any valid long option; the leading two
dashes may not be entered and the option may not be abbreviated.
This default name may be changed on the command line (*note
gpgsm-option --options::). You should backup this file.

`policies.txt'
This is a list of allowed CA policies. This file should list the
object identifiers of the policies line by line. Empty lines and
lines starting with a hash mark are ignored. Policies missing in
this file and not marked as critical in the certificate will print
only a warning; certificates with policies marked as critical and
not listed in this file will fail the signature verification. You
should backup this file.

For example, to allow only the policy 2.289.9.9, the file should
look like this:

# Allowed policies
2.289.9.9

`qualified.txt'
This is the list of root certificates used for qualified
certificates. They are defined as certificates capable of
creating legally binding signatures in the same way as handwritten
signatures are. Comments start with a hash mark and empty lines
are ignored. Lines do have a length limit but this is not a
serious limitation as the format of the entries is fixed and
checked by gpgsm: A non-comment line starts with optional
whitespace, followed by exactly 40 hex character, white space and
a lowercased 2 letter country code. Additional data delimited with
by a white space is current ignored but might late be used for
other purposes.

Note that even if a certificate is listed in this file, this does
not mean that the certificate is trusted; in general the
certificates listed in this file need to be listed also in
`trustlist.txt'.

This is a global file an installed in the data directory (e.g.
`/usr/share/gnupg/qualified.txt'). GnuPG installs a suitable file
with root certificates as used in Germany. As new Root-CA
certificates may be issued over time, these entries may need to be
updated; new distributions of this software should come with an
updated list but it is still the responsibility of the
Administrator to check that this list is correct.

Everytime `gpgsm' uses a certificate for signing or verification
this file will be consulted to check whether the certificate under
question has ultimately been issued by one of these CAs. If this
is the case the user will be informed that the verified signature
represents a legally binding ("qualified") signature. When
creating a signature using such a certificate an extra prompt will
be issued to let the user confirm that such a legally binding
signature shall really be created.

Because this software has not yet been approved for use with such
certificates, appropriate notices will be shown to indicate this
fact.

`help.txt'
This is plain text file with a few help entries used with
`pinentry' as well as a large list of help items for `gpg' and
`gpgsm'. The standard file has English help texts; to install
localized versions use filenames like `help.LL.txt' with LL
denoting the locale. GnuPG comes with a set of predefined help
files in the data directory (e.g. `/usr/share/gnupg/help.de.txt')
and allows overriding of any help item by help files stored in the
system configuration directory (e.g. `/etc/gnupg/help.de.txt').
For a reference of the help file's syntax, please see the installed
`help.txt' file.

`com-certs.pem'
This file is a collection of common certificates used to populated
a newly created `pubring.kbx'. An administrator may replace this
file with a custom one. The format is a concatenation of PEM
encoded X.509 certificates. This global file is installed in the
data directory (e.g. `/usr/share/gnupg/com-certs.pem').

Note that on larger installations, it is useful to put predefined
files into the directory `/etc/skel/.gnupg/' so that newly created users
start up with a working configuration. For existing users a small
helper script is provided to create these files (*note addgnupghome::).

For internal purposes gpgsm creates and maintains a few other files;
they all live in in the current home directory (*note option
--homedir::). Only `gpgsm' may modify these files.

`pubring.kbx'
This a database file storing the certificates as well as meta
information. For debugging purposes the tool `kbxutil' may be
used to show the internal structure of this file. You should
backup this file.

`random_seed'
This content of this file is used to maintain the internal state
of the random number generator across invocations. The same file
is used by other programs of this software too.

`S.gpg-agent'
If this file exists and the environment variable `GPG_AGENT_INFO'
is not set, `gpgsm' will first try to connect to this socket for
accessing `gpg-agent' before starting a new `gpg-agent' instance.
Under Windows this socket (which in reality be a plain file
describing a regular TCP listening port) is the standard way of
connecting the `gpg-agent'.

File: gnupg.info, Node: GPGSM Examples, Next: Unattended Usage, Prev: GPGSM Configuration, Up: Invoking GPGSM

4.4 Examples
============

$ gpgsm -er goo AT bar.net <plaintext >ciphertext

File: gnupg.info, Node: Unattended Usage, Next: GPGSM Protocol, Prev: GPGSM Examples, Up: Invoking GPGSM

4.5 Unattended Usage
====================

`gpgsm' is often used as a backend engine by other software. To help
with this a machine interface has been defined to have an unambiguous
way to do this. This is most likely used with the `--server' command
but may also be used in the standard operation mode by using the
`--status-fd' option.

* Menu:

* Automated signature checking:: Automated signature checking.
* CSR and certificate creation:: CSR and certificate creation.

File: gnupg.info, Node: Automated signature checking, Next: CSR and certificate creation, Up: Unattended Usage

4.5.1 Automated signature checking
----------------------------------

It is very important to understand the semantics used with signature
verification. Checking a signature is not as simple as it may sound and
so the operation is a bit complicated. In most cases it is required to
look at several status lines. Here is a table of all cases a signed
message may have:

The signature is valid
This does mean that the signature has been successfully verified,
the certificates are all sane. However there are two subcases with
important information: One of the certificates may have expired
or a signature of a message itself as expired. It is a sound
practise to consider such a signature still as valid but
additional information should be displayed. Depending on the
subcase `gpgsm' will issue these status codes:
signature valid and nothing did expire
`GOODSIG', `VALIDSIG', `TRUST_FULLY'

signature valid but at least one certificate has expired
`EXPKEYSIG', `VALIDSIG', `TRUST_FULLY'

signature valid but expired
`EXPSIG', `VALIDSIG', `TRUST_FULLY' Note, that this case is
currently not implemented.

The signature is invalid
This means that the signature verification failed (this is an
indication of af a transfer error, a program error or tampering
with the message). `gpgsm' issues one of these status codes
sequences:
``BADSIG''

``GOODSIG', `VALIDSIG' `TRUST_NEVER''

Error verifying a signature
For some reason the signature could not be verified, i.e. it
cannot be decided whether the signature is valid or invalid. A
common reason for this is a missing certificate.

File: gnupg.info, Node: CSR and certificate creation, Prev: Automated signature checking, Up: Unattended Usage

4.5.2 CSR and certificate creation
----------------------------------

*Please notice*: The immediate creation of certificates is only
supported by GnuPG version 2.1 or later. With a 2.0 version you may
only create a CSR.

The command `--gen-key' may be used along with the option `--batch' to
either create a certificate signing request (CSR) or an X.509
certificate. The is controlled by a parameter file; the format of this
file is as follows:

* Text only, line length is limited to about 1000 characters.

* UTF-8 encoding must be used to specify non-ASCII characters.

* Empty lines are ignored.

* Leading and trailing while space is ignored.

* A hash sign as the first non white space character indicates a
comment line.

* Control statements are indicated by a leading percent sign, the
arguments are separated by white space from the keyword.

* Parameters are specified by a keyword, followed by a colon.
Arguments are separated by white space.

* The first parameter must be `Key-Type', control statements may be
placed anywhere.

* The order of the parameters does not matter except for `Key-Type'
which must be the first parameter. The parameters are only used
for the generated CSR/certificate; parameters from previous sets
are not used. Some syntactically checks may be performed.

* Key generation takes place when either the end of the parameter
file is reached, the next `Key-Type' parameter is encountered or
at the control statement `%commit' is encountered.

Control statements:

%echo TEXT
Print TEXT as diagnostic.

%dry-run
Suppress actual key generation (useful for syntax checking).

%commit
Perform the key generation. Note that an implicit commit is done
at the next Key-Type parameter.

General Parameters:

Key-Type: ALGO
Starts a new parameter block by giving the type of the primary
key. The algorithm must be capable of signing. This is a required
parameter. The only supported value for ALGO is `rsa'.

Key-Length: NBITS
The requested length of a generated key in bits. Defaults to 2048.

Key-Grip: HEXSTRING
This is optional and used to generate a CSR or certificatet for an
already existing key. Key-Length will be ignored when given.

Key-Usage: USAGE-LIST
Space or comma delimited list of key usage, allowed values are
`encrypt', `sign' and `cert'. This is used to generate the
keyUsage extension. Please make sure that the algorithm is
capable of this usage. Default is to allow encrypt and sign.

Name-DN: SUBJECT-NAME
This is the Distinguished Name (DN) of the subject in RFC-2253
format.

Name-Email: STRING
This is an email address for the altSubjectName. This parameter is
optional but may occur several times to add several email
addresses to a certificate.

Name-DNS: STRING
The is an DNS name for the altSubjectName. This parameter is
optional but may occur several times to add several DNS names to a
certificate.

Name-URI: STRING
This is an URI for the altSubjectName. This parameter is optional
but may occur several times to add several URIs to a certificate.

Additional parameters used to create a certificate (in contrast to a
certificate signing request):

Serial: SN
If this parameter is given an X.509 certificate will be generated.
SN is expected to be a hex string representing an unsigned integer
of arbitary length. The special value `random' can be used to
create a 64 bit random serial number.

Issuer-DN: ISSUER-NAME
This is the DN name of the issuer in rfc2253 format. If it is not
set it will default to the subject DN and a special GnuPG
extension will be included in the certificate to mark it as a
standalone certificate.

Creation-Date: ISO-DATE
Not-Before: ISO-DATE
Set the notBefore date of the certificate. Either a date like
`1986-04-26' or `1986-04-26 12:00' or a standard ISO timestamp
like `19860426T042640' may be used. The time is considered to be
UTC. If it is not given the current date is used.

Expire-Date: ISO-DATE
Not-After: ISO-DATE
Set the notAfter date of the certificate. Either a date like
`2063-04-05' or `2063-04-05 17:00' or a standard ISO timestamp
like `20630405T170000' may be used. The time is considered to be
UTC. If it is not given a default value in the not too far future
is used.

Signing-Key: KEYGRIP
This gives the keygrip of the key used to sign the certificate.
If it is not given a self-signed certificate will be created. For
compatibility with future versions, it is suggested to prefix the
keygrip with a `&'.

Hash-Algo: HASH-ALGO
Use HASH-ALGO for this CSR or certificate. The supported hash
algorithms are: `sha1', `sha256', `sha384' and `sha512'; they may
also be specified with uppercase letters. The default is `sha1'.

File: gnupg.info, Node: GPGSM Protocol, Prev: Unattended Usage, Up: Invoking GPGSM

4.6 The Protocol the Server Mode Uses.
======================================

Description of the protocol used to access `GPGSM'. `GPGSM' does
implement the Assuan protocol and in addition provides a regular
command line interface which exhibits a full client to this protocol
(but uses internal linking). To start `gpgsm' as a server the command
line the option `--server' must be used. Additional options are
provided to select the communication method (i.e. the name of the
socket).

We assume that the connection has already been established; see the
Assuan manual for details.

* Menu:

* GPGSM ENCRYPT:: Encrypting a message.
* GPGSM DECRYPT:: Decrypting a message.
* GPGSM SIGN:: Signing a message.
* GPGSM VERIFY:: Verifying a message.
* GPGSM GENKEY:: Generating a key.
* GPGSM LISTKEYS:: List available keys.
* GPGSM EXPORT:: Export certificates.
* GPGSM IMPORT:: Import certificates.
* GPGSM DELETE:: Delete certificates.
* GPGSM GETINFO:: Information about the process

File: gnupg.info, Node: GPGSM ENCRYPT, Next: GPGSM DECRYPT, Up: GPGSM Protocol

4.6.1 Encrypting a Message
--------------------------

Before encryption can be done the recipient must be set using the
command:

RECIPIENT USERID

Set the recipient for the encryption. USERID should be the internal
representation of the key; the server may accept any other way of
specification. If this is a valid and trusted recipient the server
does respond with OK, otherwise the return is an ERR with the reason why
the recipient cannot be used, the encryption will then not be done for
this recipient. If the policy is not to encrypt at all if not all
recipients are valid, the client has to take care of this. All
`RECIPIENT' commands are cumulative until a `RESET' or an successful
`ENCRYPT' command.

INPUT FD[=N] [--armor|--base64|--binary]

Set the file descriptor for the message to be encrypted to N.
Obviously the pipe must be open at that point, the server establishes
its own end. If the server returns an error the client should consider
this session failed. If N is not given, this commands uses the last
file descriptor passed to the application. *Note the assuan_sendfd
function: (assuan)fun-assuan_sendfd, on how to do descriptor passing.

The `--armor' option may be used to advice the server that the input
data is in PEM format, `--base64' advices that a raw base-64 encoding
is used, `--binary' advices of raw binary input (BER). If none of
these options is used, the server tries to figure out the used
encoding, but this may not always be correct.

OUTPUT FD[=N] [--armor|--base64]

Set the file descriptor to be used for the output (i.e. the encrypted
message). Obviously the pipe must be open at that point, the server
establishes its own end. If the server returns an error he client
should consider this session failed.

The option armor encodes the output in PEM format, the `--base64'
option applies just a base 64 encoding. No option creates binary
output (BER).

The actual encryption is done using the command

ENCRYPT

It takes the plaintext from the `INPUT' command, writes to the
ciphertext to the file descriptor set with the `OUTPUT' command, take
the recipients from all the recipients set so far. If this command
fails the clients should try to delete all output currently done or
otherwise mark it as invalid. `GPGSM' does ensure that there will not
be any security problem with leftover data on the output in this case.

This command should in general not fail, as all necessary checks have
been done while setting the recipients. The input and output pipes are
closed.

File: gnupg.info, Node: GPGSM DECRYPT, Next: GPGSM SIGN, Prev: GPGSM ENCRYPT, Up: GPGSM Protocol

4.6.2 Decrypting a message
--------------------------

Input and output FDs are set the same way as in encryption, but `INPUT'
refers to the ciphertext and output to the plaintext. There is no need
to set recipients. `GPGSM' automatically strips any S/MIME headers
from the input, so it is valid to pass an entire MIME part to the INPUT
pipe.

The encryption is done by using the command

DECRYPT

It performs the decrypt operation after doing some check on the
internal state. (e.g. that all needed data has been set). Because it
utilizes the GPG-Agent for the session key decryption, there is no need
to ask the client for a protecting passphrase - GpgAgent takes care of
this by requesting this from the user.

File: gnupg.info, Node: GPGSM SIGN, Next: GPGSM VERIFY, Prev: GPGSM DECRYPT, Up: GPGSM Protocol

4.6.3 Signing a Message
-----------------------

Signing is usually done with these commands:

INPUT FD[=N] [--armor|--base64|--binary]

This tells `GPGSM' to read the data to sign from file descriptor N.

OUTPUT FD[=M] [--armor|--base64]

Write the output to file descriptor M. If a detached signature is
requested, only the signature is written.

SIGN [--detached]

Sign the data set with the INPUT command and write it to the sink
set by OUTPUT. With `--detached', a detached signature is created
(surprise).

The key used for signing is the default one or the one specified in
the configuration file. To get finer control over the keys, it is
possible to use the command

SIGNER USERID

to the signer's key. USERID should be the internal representation
of the key; the server may accept any other way of specification. If
this is a valid and trusted recipient the server does respond with OK,
otherwise the return is an ERR with the reason why the key cannot be
used, the signature will then not be created using this key. If the
policy is not to sign at all if not all keys are valid, the client has
to take care of this. All `SIGNER' commands are cumulative until a
`RESET' is done. Note that a `SIGN' does not reset this list of
signers which is in contrats to the `RECIPIENT' command.

File: gnupg.info, Node: GPGSM VERIFY, Next: GPGSM GENKEY, Prev: GPGSM SIGN, Up: GPGSM Protocol

4.6.4 Verifying a Message
-------------------------

To verify a mesage the command:

VERIFY

is used. It does a verify operation on the message send to the input
FD. The result is written out using status lines. If an output FD was
given, the signed text will be written to that. If the signature is a
detached one, the server will inquire about the signed material and the
client must provide it.

File: gnupg.info, Node: GPGSM GENKEY, Next: GPGSM LISTKEYS, Prev: GPGSM VERIFY, Up: GPGSM Protocol

4.6.5 Generating a Key
----------------------

This is used to generate a new keypair, store the secret part in the
PSE and the public key in the key database. We will probably add
optional commands to allow the client to select whether a hardware
token is used to store the key. Configuration options to `GPGSM' can
be used to restrict the use of this command.

GENKEY

`GPGSM' checks whether this command is allowed and then does an
INQUIRY to get the key parameters, the client should then send the key
parameters in the native format:

S: INQUIRE KEY_PARAM native
C: D foo:fgfgfg
C: D bar
C: END

Please note that the server may send Status info lines while reading
the data lines from the client. After this the key generation takes
place and the server eventually does send an ERR or OK response.
Status lines may be issued as a progress indicator.

File: gnupg.info, Node: GPGSM LISTKEYS, Next: GPGSM EXPORT, Prev: GPGSM GENKEY, Up: GPGSM Protocol

4.6.6 List available keys
-------------------------

To list the keys in the internal database or using an external key
provider, the command:

LISTKEYS PATTERN

is used. To allow multiple patterns (which are ORed during the
search) quoting is required: Spaces are to be translated into "+" or
into "%20"; in turn this requires that the usual escape quoting rules
are done.

LISTSECRETKEYS PATTERN

Lists only the keys where a secret key is available.

The list commands commands are affected by the option

OPTION list-mode=MODE

where mode may be:
`0'
Use default (which is usually the same as 1).

`1'
List only the internal keys.

`2'
List only the external keys.

`3'
List internal and external keys.

Note that options are valid for the entire session.

File: gnupg.info, Node: GPGSM EXPORT, Next: GPGSM IMPORT, Prev: GPGSM LISTKEYS, Up: GPGSM Protocol

4.6.7 Export certificates
-------------------------

To export certificate from the internal key database the command:

EXPORT [--data [--armor] [--base64]] [--] PATTERN

is used. To allow multiple patterns (which are ORed) quoting is
required: Spaces are to be translated into "+" or into "%20"; in turn
this requires that the usual escape quoting rules are done.

If the `--data' option has not been given, the format of the output
depends on what was set with the OUTPUT command. When using PEM
encoding a few informational lines are prepended.

If the `--data' has been given, a target set via OUTPUT is ignored
and the data is returned inline using standard `D'-lines. This avoids
the need for an extra file descriptor. In this case the options
`--armor' and `--base64' may be used in the same way as with the OUTPUT
command.

File: gnupg.info, Node: GPGSM IMPORT, Next: GPGSM DELETE, Prev: GPGSM EXPORT, Up: GPGSM Protocol

4.6.8 Import certificates
-------------------------

To import certificates into the internal key database, the command

IMPORT [--re-import]

is used. The data is expected on the file descriptor set with the
`INPUT' command. Certain checks are performed on the certificate.
Note that the code will also handle PKCS#12 files and import private
keys; a helper program is used for that.

With the option `--re-import' the input data is expected to a be a
linefeed separated list of fingerprints. The command will re-import
the corresponding certificates; that is they are made permanent by
removing their ephemeral flag.

File: gnupg.info, Node: GPGSM DELETE, Next: GPGSM GETINFO, Prev: GPGSM IMPORT, Up: GPGSM Protocol

4.6.9 Delete certificates
-------------------------

To delete a certificate the command

DELKEYS PATTERN

is used. To allow multiple patterns (which are ORed) quoting is
required: Spaces are to be translated into "+" or into "%20"; in turn
this requires that the usual escape quoting rules are done.

The certificates must be specified unambiguously otherwise an error
is returned.

File: gnupg.info, Node: GPGSM GETINFO, Prev: GPGSM DELETE, Up: GPGSM Protocol

4.6.10 Return information about the process
-------------------------------------------

This is a multipurpose function to return a variety of information.

GETINFO WHAT

The value of WHAT specifies the kind of information returned:
`version'
Return the version of the program.

`pid'
Return the process id of the process.

`agent-check'
Return success if the agent is running.

`cmd_has_option CMD OPT'
Return success if the command CMD implements the option OPT. The
leading two dashes usually used with OPT shall not be given.

File: gnupg.info, Node: Invoking SCDAEMON, Next: Specify a User ID, Prev: Invoking GPGSM, Up: Top

5 Invoking the SCDAEMON
***********************

The `scdaemon' is a daemon to manage smartcards. It is usually invoked
by `gpg-agent' and in general not used directly.

*Note Option Index::, for an index to `scdaemon''s commands and
options.

* Menu:

* Scdaemon Commands:: List of all commands.
* Scdaemon Options:: List of all options.
* Card applications:: Description of card applications.
* Scdaemon Configuration:: Configuration files.
* Scdaemon Examples:: Some usage examples.
* Scdaemon Protocol:: The protocol the daemon uses.

File: gnupg.info, Node: Scdaemon Commands, Next: Scdaemon Options, Up: Invoking SCDAEMON

5.1 Commands
============

Commands are not distinguished from options except for the fact that
only one command is allowed.

`--version'
Print the program version and licensing information. Not that you
can abbreviate this command.

`--help, -h'
Print a usage message summarizing the most useful command-line
options. Not that you can abbreviate this command.

`--dump-options'
Print a list of all available options and commands. Not that you
can abbreviate this command.

`--server'
Run in server mode and wait for commands on the `stdin'. This is
default mode is to create a socket and listen for commands there.

`--multi-server'
Run in server mode and wait for commands on the `stdin' as well as
on an additional Unix Domain socket. The server command `GETINFO'
may be used to get the name of that extra socket.

`--daemon'
Run the program in the background. This option is required to
prevent it from being accidentally running in the background.

File: gnupg.info, Node: Scdaemon Options, Next: Card applications, Prev: Scdaemon Commands, Up: Invoking SCDAEMON

5.2 Option Summary
==================

`--options FILE'
Reads configuration from FILE instead of from the default per-user
configuration file. The default configuration file is named
`scdaemon.conf' and expected in the `.gnupg' directory directly
below the home directory of the user.