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Revision 1.6, Wed May 23 02:08:40 2018 UTC (5 years, 10 months ago) by christos
Branch: MAIN
CVS Tags: phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, netbsd-9-base, netbsd-9-3-RELEASE, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-10-base, netbsd-10-0-RELEASE, netbsd-10-0-RC6, netbsd-10-0-RC5, netbsd-10-0-RC4, netbsd-10-0-RC3, netbsd-10-0-RC2, netbsd-10-0-RC1, netbsd-10, is-mlppp-base, is-mlppp, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, HEAD
Changes since 1.5: +6 -2 lines

Add cross references to the openssl man pages.

.\" $NetBSD: hmac.3,v 1.6 2018/05/23 02:08:40 christos Exp $
.\"
.\" Copyright (c) 2016 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Christos Zoulas.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\"TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\"
.Dd May 22, 2018
.Dt HMAC 3
.Os
.Sh NAME
.Nm hmac
.Nd compute a key-Hash Message Authentication Code
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft ssize_t
.Fn hmac "const char *hname" "const void *key" "size_t klen" "const void *text" "size_t tlen" "void *digest" "size_t dlen"
.Sh DESCRIPTION
The
.Fn hmac
function computes the key-Hash Message Authentication Code per
.Tn RFC 2104
and places the result in
.Fa digest
writing up to
.Fa dlen
bytes.
The actual number of bytes that would be written is returned.
.Pp
The hash functions supported are: md2, md4, md5, rmd160, sha1, sha224,
sha256, sha384, and sha512.
.Sh RETURN VALUES
The
.Fn hmac
function returns
.Dv \-1
if the
.Fa hname
is not found.
Otherwise the actual length of the digest string is returned (which could
be bigger or smaller than
.Fa dlen ) .
This length depends on the hashing function selected.
.Sh SEE ALSO
.Xr md2 3 ,
.Xr md4 3 ,
.Xr md5 3 ,
.Xr openssl_HMAC 3 ,
.Xr openssl_MD2 3 ,
.Xr openssl_MD4 3 ,
.Xr openssl_MD5 3 ,
.Xr rmd160 3 ,
.Xr sha1 3 ,
.Xr sha2 3
.Sh STANDARDS
.Rs
.%R RFC 2104
.Re
.Sh NOTES
The maximum digest length has been extended from
.Dv 64
to
.Dv 128
bytes to handle SHA2.
.Sh HISTORY
The
.Fn hmac
function appeared in
.Nx 8 .