.\"	$OpenBSD: md5.9,v 1.14 2015/11/24 14:58:56 jmc Exp $
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.\" Copyright (c) 1996	Michael Shalayeff
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.Dd $Mdocdate: November 24 2015 $
.Dt MD5INIT 9
.Os
.Sh NAME
.Nm MD5Init ,
.Nm MD5Transform
.Nd message digest routines
.Sh SYNOPSIS
.In sys/kernel.h
.Ft void
.Fn MD5Init "u_int32_t buf[4]"
.Ft void
.Fn MD5Transform "u_int32_t buf[4]" "u_int32_t const in[16]"
.Sh DESCRIPTION
The
.Nm
module implements the RSA Data Security, Inc.
MD5 Message-Digest Algorithm (MD5).
It produces 128-bit MD5 Digest of data.
.Bl -hang -width MD5Transform
.It Fn MD5Init
must be called just before
.Fn MD5Transform
will be used to produce a digest.
The
.Fa buf
argument is the storage for the digest being produced on subsequent
calls to the
.Fn MD5Transform
routine.
.It Fn MD5Transform
is the core of the MD5 algorithm, this alters an existing MD5 hash
kept in
.Fa buf
to reflect the addition of 16 longwords
of new data passed in
.Fa in
argument.
.El
.Sh COPYRIGHTS
The code for MD5 transform was taken from Colin Plumb's
implementation, which has been placed in the public domain.
The MD5 cryptographic checksum was devised by Ronald Rivest, and is
documented in RFC 1321, "The MD5 Message Digest Algorithm".
.Sh SEE ALSO
.Xr random 4 ,
.Xr arc4random 9