crypt(3C)                        DG/UX 5.4.2                       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
       function.

       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).

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.



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