CIPHER(3)                 BSD Library Functions Manual                 CIPHER(3)

     setkey, encrypt, des_setkey, des_cipher, — DES encryption

     setkey(char *key);

     encrypt(char *block, int flag);

     des_setkey(const char *key);

     des_cipher(const char *in, char *out, long salt, int count);

     The functions, encrypt(), setkey(), des_setkey() and des_cipher() provide
     access to the DES algorithm.  setkey() is passed a 64-byte array of binary
     values (numeric 0 or 1).  A 56-bit key is extracted from this array by
     dividing the array into groups of 8, and ignoring the last bit in each
     group.  That bit is reserved for a byte parity check by DES, but is ignored
     by these functions.

     The block argument to encrypt() is also a 64-byte array of binary values.
     If the value of flag is 0, block is encrypted otherwise it is decrypted.
     The result is returned in the original array block after using the key
     specified by setkey() to process it.

     The argument to des_setkey() is a character array of length 8.  The least
     significant bit (the parity bit) in each character is ignored, and the
     remaining bits are concatenated to form a 56-bit key.  The function
     des_cipher() encrypts (or decrypts if count is negative) the 64-bits stored
     in the 8 characters at in using abs(3) of count iterations of DES and
     stores the 64-bit result in the 8 characters at out (which may be the same
     as in ).  The salt introduces disorder in the DES algorithm in one of
     16777216 or 4096 possible ways (ie. with 24 or 12 bits: if bit i of the
     salt is set, then bits i and i+24 are swapped in the DES E-box output).

     The functions setkey(), encrypt(), des_setkey(), and des_cipher() return 0
     on success and 1 on failure.

     The setkey() and des_setkey() functions manipulate the same key space.

     login(1), passwd(1), crypt(3), getpass(3), passwd(5)

     This library (FreeSec 1.0) was developed outside the United States of
     America as an unencumbered replacement for the U.S.-only NetBSD libcrypt
     encryption library.  Users should be aware that this code (and programs
     staticly linked with it) may not be exported from the U.S., although it
     apparently can be imported.

     David Burren <davidb@werj.com.au>

FreeSec 1.0                       March 9, 1994                      FreeSec 1.0