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 utilize  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 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 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 initialization vector upon return.

ERRORS

       [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 argument to routine.

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

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.

Debian                                           October 6, 1987                                    DES_CRYPT(3)