NAME

       encrypt - encoding function (CRYPT)

SYNOPSIS

       #include <unistd.h>

       void encrypt(char block[64], int edflag);

DESCRIPTION

       The  encrypt()  function  shall  provide  access to an implementation-defined encoding algorithm. The key
       generated by setkey() is used to encrypt the string block with encrypt().

       The block argument to encrypt() shall be an array of length 64  bytes  containing  only  the  bytes  with
       values  of  0  and 1. The array is modified in place to a similar array using the key set by setkey(). If
       edflag is 0, the argument is encoded.  If edflag is 1, the argument may be decoded (see  the  APPLICATION
       USAGE section); if the argument is not decoded, errno shall be set to [ENOSYS].

       The  encrypt()  function  shall  not change the setting of errno if successful. An application wishing to
       check for error situations should set errno to 0 before calling  encrypt().   If  errno  is  non-zero  on
       return, an error has occurred.

       The  encrypt()  function  need  not  be reentrant. A function that is not required to be reentrant is not
       required to be thread-safe.

RETURN VALUE

       The encrypt() function shall not return a value.

ERRORS

       The encrypt() function shall fail if:

       ENOSYS The functionality is not supported on this implementation.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Historical implementations of the encrypt() function used a rather primitive encoding algorithm.

       In some environments, decoding might not be implemented. This is related to some Government  restrictions
       on  encryption  and  decryption routines. Historical practice has been to ship a different version of the
       encryption library without the decryption feature in the routines supplied. Thus the exported version  of
       encrypt() does encoding but not decoding.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       crypt() , setkey() , the Base Definitions volume of IEEE Std 1003.1-2001, <unistd.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .