ENCRYPT(3P)                                         POSIX Programmer's Manual                                        ENCRYPT(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

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,  Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                   ENCRYPT(3P)