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.TH SETKEY "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"

.SH PROLOG

This manual page is part of the POSIX Programmer's Manual.

The Linux implementation of this interface may differ (consult

the corresponding Linux manual page for details of Linux behavior),

or the interface may not be implemented on Linux.

.SH NAME

setkey

\(em set encoding key

(\fBCRYPT\fP)

.SH SYNOPSIS

.LP

.nf

#include <stdlib.h>

.P

void setkey(const char *\fIkey\fP);

.fi

.SH DESCRIPTION

The

\fIsetkey\fR()

function provides access to an implementation-defined encoding

algorithm. The argument of

\fIsetkey\fR()

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

.IR block

passed to

\fIencrypt\fR().

.P

The

\fIsetkey\fR()

function shall not change the setting of

.IR errno

if successful. An application wishing to check for error situations

should set

.IR errno

to 0 before calling

\fIsetkey\fR().

If

.IR errno

is non-zero on return, an error has occurred.

.P

The

\fIsetkey\fR()

function need not be thread-safe.

.SH "RETURN VALUE"

No values are returned.

.SH ERRORS

The

\fIsetkey\fR()

function shall fail if:

.TP

.BR ENOSYS

The functionality is not supported on this implementation.

.LP

.IR "The following sections are informative."

.SH EXAMPLES

None.

.SH "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

\fIencrypt\fR()

does encoding but not decoding.

.SH RATIONALE

None.

.SH "FUTURE DIRECTIONS"

None.

.SH "SEE ALSO"

.IR "\fIcrypt\fR\^(\|)",

.IR "\fIencrypt\fR\^(\|)"

.P

The Base Definitions volume of POSIX.1\(hy2008,

.IR "\fB<stdlib.h>\fP"

.SH COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form

from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology

-- Portable Operating System Interface (POSIX), The Open Group Base

Specifications Issue 7, Copyright (C) 2013 by the Institute of

Electrical and Electronics Engineers, Inc and The Open Group.

(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

Any typographical or formatting errors that appear

in this page are most likely

to have been introduced during the conversion of the source files to

man page format. To report such errors, see

https://www.kernel.org/doc/man-pages/reporting_bugs.html .