des_crypt(3C)                                       des_crypt(3C)



NAME
     descrypt, ecbcrypt, cbccrypt, dessetparity - fast DES
     encryption

SYNOPSIS
     #include <des/descrypt.h>

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

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

     void dessetparity(key)
     char *key;

DESCRIPTION
     ecbcrypt() and cbccrypt() implement the NBS DES (Data
     Encryption Standard).  These routines are faster and more
     general purpose than crypt(3C).  They also are able to util-
     ize DES hardware if it is available.  ecbcrypt() encrypts
     in ECB (Electronic Code Book) mode, which encrypts blocks of
     data independently.  cbccrypt() 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 parameter,
     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 dessetparity.  The second parameter, data, contains the
     data to be encrypted or decrypted. The third parameter,
     datalen, is the length in bytes of data, which must be a
     multiple of 8. The fourth parameter, 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 performed in software and the routine returns
     DESERR_NOHWDEVICE. For cbccrypt, the parameter ivec is the
     the 8-byte initialization vector for the chaining.  It is
     updated to the next initialization vector upon return.





Page 1                        CX/UX Programmer's Reference Manual

des_crypt(3C)                                       des_crypt(3C)



SEE ALSO
     crypt(3C)

DIAGNOSTICS
     DESERR_NONE         No error.
     DESERR_NOHWDEVICE   Encryption succeeded, but done in
                         software instead of the requested
                         hardware.
     DESERR_HWERR        An error occurred in the hardware or
                         driver.
     DESERR_BADPARAM     Bad parameter to routine.

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

RESTRICTIONS
     These routines are not available for export outside the U.S.
     To access them, the link editor must be invoked manually,
     and -ldes must be specified after -lc.




































Page 2                        CX/UX Programmer's Reference Manual