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 .