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+'\" t
+.\"  Copyright 2003 walter harms (walter.harms@informatik.uni-oldenburg.de)
+.\"
+.\" SPDX-License-Identifier: GPL-1.0-or-later
+.\"
+.\"  this is the 3rd type of interface for cryptographic routines
+.\"  1. encrypt() expects a bit field
+.\"  2. cbc_crypt() byte values
+.\"  3. xencrypt() a hexstring
+.\"  to bad to be true :(
+.\"
+.TH XCRYPT 3 2024-05-02 "Linux man-pages (unreleased)"
+.SH NAME
+xencrypt, xdecrypt, passwd2des \- RFS password encryption
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
+.SH SYNOPSIS
+.nf
+.B "#include <rpc/des_crypt.h>"
+.P
+.BI "void passwd2des(char " *passwd ", char *" key ");"
+.P
+.BI "int xencrypt(char *" secret ", char *" passwd ");"
+.BI "int xdecrypt(char *" secret ", char *" passwd ");"
+.fi
+.SH DESCRIPTION
+.BR WARNING :
+Do not use these functions in new code.
+They do not achieve any type of acceptable cryptographic security guarantees.
+.P
+The function
+.BR passwd2des ()
+takes a character string
+.I passwd
+of arbitrary length and fills a character array
+.I key
+of length 8.
+The array
+.I key
+is suitable for use as DES key.
+It has odd parity set in bit 0 of each byte.
+Both other functions described here use this function to turn their
+argument
+.I passwd
+into a DES key.
+.P
+The
+.BR xencrypt ()
+function takes the ASCII character string
+.I secret
+given in hex,
+.\" (over the alphabet 0123456789abcdefABCDEF),
+which must have a length that is a multiple of 16,
+encrypts it using the DES key derived from
+.I passwd
+by
+.BR passwd2des (),
+and outputs the result again in
+.I secret
+as a hex string
+.\" (over the alphabet 0123456789abcdef)
+of the same length.
+.P
+The
+.BR xdecrypt ()
+function performs the converse operation.
+.SH RETURN VALUE
+The functions
+.BR xencrypt ()
+and
+.BR xdecrypt ()
+return 1 on success and 0 on error.
+.SH ATTRIBUTES
+For an explanation of the terms used in this section, see
+.BR attributes (7).
+.TS
+allbox;
+lbx lb lb
+l l l.
+Interface	Attribute	Value
+T{
+.na
+.nh
+.BR passwd2des (),
+.BR xencrypt (),
+.BR xdecrypt ()
+T}	Thread safety	MT-Safe
+.TE
+.SH VERSIONS
+These functions are available since glibc 2.1.
+.SH BUGS
+The prototypes are missing from the abovementioned include file.
+.SH SEE ALSO
+.BR cbc_crypt (3)