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DES_CRYPT(3)             BSD Library Functions Manual             DES_CRYPT(3)

NAME
     des_crypt, ecb_crypt, cbc_crypt, des_setparity — 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);

DESCRIPTION
     The ecb_crypt() and cbc_crypt() functions implement the NBS DES (Data Encryption Standard).
     These routines are faster and more general purpose than crypt(3).  They also are able to uti‐
     lize DES hardware if it is available.  The ecb_crypt() function encrypts in ECB (Electronic
     Code Book) mode, which encrypts blocks of data independently.  The cbc_crypt() function en‐
     crypts 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 direc‐
     tion 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 cbc_crypt(), the ivec
     argument is the 8-byte initialization vector for the chaining.  It is updated to the next ini‐
     tialization vector upon return.

ERRORS
     [DESERR_NONE]        No error.
     [DESERR_NOHWDEVICE]  Encryption succeeded, but done in software instead of the requested hard‐
                          ware.
     [DESERR_HWERR]       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 sta‐
     tuses.

AVAILABILITY
     The ecb_crypt(), cbc_crypt(), and des_setparity() functions are part of libtirpc.

SEE ALSO
     crypt(3)

RESTRICTIONS
     These routines are not available in RPCSRC 4.0.  This information is provided to describe the
     DES interface expected by Secure RPC.

BSD                             October 6, 1987                            BSD