.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Sat Jul 24 18:54:45 1993 by Rik Faith (faith@cs.unc.edu)
.TH MEMFROB 3  2010-09-10 "GNU" "Linux Programmer's Manual"
.SH NAME
memfrob \- frobnicate (encrypt) a memory area
.SH SYNOPSIS
.nf
.BR "#define _GNU_SOURCE" "             /* See feature_test_macros(7) */"
.B #include <string.h>
.sp
.BI "void *memfrob(void *" s ", size_t " n );
.fi
.SH DESCRIPTION
The
.BR memfrob ()
function encrypts the first \fIn\fP bytes of the
memory area \fIs\fP by exclusive-ORing each character with the number
42.
The effect can be reversed by using
.BR memfrob ()
on the
encrypted memory area.
.PP
Note that this function is not a proper encryption routine as the XOR
constant is fixed, and is only suitable for hiding strings.
.SH "RETURN VALUE"
The
.BR memfrob ()
function returns a pointer to the encrypted memory
area.
.SH "CONFORMING TO"
The
.BR memfrob ()
function is unique to the
GNU C Library.
.SH "SEE ALSO"
.BR strfry (3)