NAME
setkey - set encoding key (CRYPT)
SYNOPSIS
#include <stdlib.h>
void setkey(const char *key);
DESCRIPTION
The setkey() function provides access to an implementation-defined
encoding algorithm. The argument of setkey() is an array of length 64
bytes containing only the bytes with numerical value of 0 and 1. If
this string is divided into groups of 8, the low-order bit in each
group is ignored; this gives a 56-bit key which is used by the
algorithm. This is the key that shall be used with the algorithm to
encode a string block passed to encrypt().
The setkey() 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 setkey(). If errno is non-zero on
return, an error has occurred.
The setkey() function need not be reentrant. A function that is not
required to be reentrant is not required to be thread-safe.
RETURN VALUE
No values are returned.
ERRORS
The setkey() function shall fail if:
ENOSYS The functionality is not supported on this implementation.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
Decoding need not be implemented in all environments. This is related
to government restrictions in some countries 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() , encrypt() , the Base Definitions volume of
IEEE Std 1003.1-2001, <stdlib.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 .