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DES_CRYPT(3)               Linux Programmer's Manual              DES_CRYPT(3)



NAME
       des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED - fast DES encryption

SYNOPSIS
       #include <rpc/des_crypt.h>

       int ecb_crypt(char *key, char *data, unsigned datalen,
                     unsigned mode);

       int cbc_crypt(char *key, char *data, unsigned datalen,
                     unsigned mode, char *ivec);

       void des_setparity(char *key);

       int DES_FAILED(int status);

DESCRIPTION
       ecb_crypt()  and  cbc_crypt()  implement the NBS DES (Data Encryption Standard).  These routines are faster and
       more general purpose than crypt(3).   They  also  are  able  to  utilize  DES  hardware  if  it  is  available.
       ecb_crypt()  encrypts  in  ECB  (Electronic  Code  Book)  mode,  which  encrypts  blocks of data independently.
       cbc_crypt() encrypts in CBC (Cipher Block Chaining) mode, which chains together successive  blocks.   CBC  mode
       protects  against insertions, deletions and substitutions of blocks.  Also, regularities in the clear text will
       not appear in the cipher text.

       Here is how to use these routines.  The first argument, key, is the 8-byte encryption key with parity.  To  set
       the  key's  parity,  which  for  DES is in the low bit of each byte, use des_setparity().  The second argument,
       data, contains the data to be encrypted or decrypted.  The third argument, datalen, is the length in  bytes  of
       data,  which  must  be  a multiple of 8.  The fourth argument, mode, is formed by OR 'ing together some things.
       For the encryption direction OR in either DES_ENCRYPT or DES_DECRYPT.  For software versus hardware encryption,
       OR  in  either DES_HW or DES_SW.  If DES_HW is specified, and there is no hardware, then the encryption is per-
       formed in software and the routine returns DESERR_NOHWDEVICE.  For cbc_crypt(), the argument ivec is the 8-byte
       initialization vector for the chaining.  It is updated to the next initialization vector upon return.

RETURN VALUE
       DESERR_NONE         No error.
       DESERR_NOHWDEVICE   Encryption succeeded, but done in software instead of the requested hardware.
       DESERR_HWERROR      An error occurred in the hardware or driver.
       DESERR_BADPARAM     Bad argument to routine.

       Given a result status stat, the macro DES_FAILED(stat) is false only for the first two statuses.

VERSIONS
       These routines are present in libc 4.6.27 and later, and in glibc 2.1 and later.

CONFORMING TO
       4.3BSD.  Not in POSIX.1-2001.

SEE ALSO
       des(1), crypt(3), xcrypt(3)

COLOPHON
       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



                                  2007-05-18                      DES_CRYPT(3)