crypt(3C)            COMPATIBILITY FUNCTIONS            crypt(3C)



NAME
     crypt, setkey, encrypt - generate encryption

SYNOPSIS
     #include <crypt.h>

     char *crypt (const char *key, const char *salt);

     void setkey (const char *key);

     void encrypt (char *block, int edflag);

DESCRIPTION
     crypt is the password encryption function.  It is based on a
     one-way encryption algorithm with variations intended (among
     other things) to frustrate use of  hardware  implementations
     of a key search.

     key is the input string to encrypt, for instance,  a  user's
     typed  password.   Only the first eight characters are used;
     the rest are ignored.  salt is a two-character string chosen
     from the set a-zA-Z0-9./; this string is used to perturb the
     hashing algorithm in one of 4096 different ways, after which
     the  input string is used as the key to encrypt repeatedly a
     constant string.  The returned value points to the encrypted
     input  string.  The first two characters of the return value
     are the salt itself.

     The setkey and encrypt functions provide (rather  primitive)
     access  to  the  actual  hashing algorithm.  The argument of
     setkey is a character array of length 64 containing only the
     characters  with  numerical  value  0 and 1.  This string is
     divided into groups of 8, the low-order bit in each group is
     ignored;  this  gives  a  56-bit  key  that  is set into the
     machine.  This is the key that will be used with the hashing
     algorithm to encrypt the string block with the encrypt func-
     tion.

     The block argument of encrypt is a character array of length
     64 containing only the characters with numerical value 0 and
     1.  The argument array is modified in  place  to  a  similar
     array  representing  the  bits  of the argument after having
     been subjected to the hashing algorithm using the key set by
     setkey.   The  argument edflag, indicating decryption rather
     than encryption, is ignored; use encrypt  in  libcrypt  [see
     crypt(3X)] for decryption.

SEE ALSO
     getpass(3C), crypt(3X), passwd(4).
     login(1), passwd(1) in the User's Reference Manual.





          Last change: C Programming Language Utilities         1

crypt(3C)            COMPATIBILITY FUNCTIONS            crypt(3C)



DIAGNOSTICS
     If edflag is set to anything other than zero, errno will  be
     set to ENOSYS.

NOTES
     The return value for crypt points to static  data  that  are
     overwritten by each call.
















































          Last change: C Programming Language Utilities         2