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/*
* LibSylph -- E-Mail client library
* Copyright (C) 1999-2006 Hiroyuki Yamamoto
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include <string.h>
#include "md5.h"
#include "md5_hmac.h"
/*
** Function: md5_hmac_get
** taken from the file rfc2104.txt
** originally written by Martin Schaaf <mascha@ma-scha.de>
** rewritten by Hiroyuki Yamamoto <hiro-y@kcn.ne.jp>
*/
static SMD5*
md5_hmac_get(const guchar *text, gint text_len,
const guchar *key, gint key_len)
{
SMD5 *md5;
guchar k_ipad[64]; /* inner padding -
* key XORd with ipad
*/
guchar k_opad[64]; /* outer padding -
* key XORd with opad
*/
guchar digest[S_GNET_MD5_HASH_LENGTH];
gint i;
/* start out by storing key in pads */
memset(k_ipad, 0, sizeof k_ipad);
memset(k_opad, 0, sizeof k_opad);
if (key_len > 64) {
/* if key is longer than 64 bytes reset it to key=MD5(key) */
SMD5 *tmd5;
tmd5 = s_gnet_md5_new(key, key_len);
memcpy(k_ipad, s_gnet_md5_get_digest(tmd5),
S_GNET_MD5_HASH_LENGTH);
memcpy(k_opad, s_gnet_md5_get_digest(tmd5),
S_GNET_MD5_HASH_LENGTH);
s_gnet_md5_delete(tmd5);
} else {
memcpy(k_ipad, key, key_len);
memcpy(k_opad, key, key_len);
}
/*
* the HMAC_MD5 transform looks like:
*
* MD5(K XOR opad, MD5(K XOR ipad, text))
*
* where K is an n byte key
* ipad is the byte 0x36 repeated 64 times
* opad is the byte 0x5c repeated 64 times
* and text is the data being protected
*/
/* XOR key with ipad and opad values */
for (i = 0; i < 64; i++) {
k_ipad[i] ^= 0x36;
k_opad[i] ^= 0x5c;
}
/*
* perform inner MD5
*/
md5 = s_gnet_md5_new_incremental(); /* init context for 1st
* pass */
s_gnet_md5_update(md5, k_ipad, 64); /* start with inner pad */
s_gnet_md5_update(md5, text, text_len); /* then text of datagram */
s_gnet_md5_final(md5); /* finish up 1st pass */
memcpy(digest, s_gnet_md5_get_digest(md5), S_GNET_MD5_HASH_LENGTH);
s_gnet_md5_delete(md5);
/*
* perform outer MD5
*/
md5 = s_gnet_md5_new_incremental(); /* init context for 2nd
* pass */
s_gnet_md5_update(md5, k_opad, 64); /* start with outer pad */
s_gnet_md5_update(md5, digest, 16); /* then results of 1st
* hash */
s_gnet_md5_final(md5); /* finish up 2nd pass */
return md5;
}
void
md5_hmac(guchar *digest,
const guchar *text, gint text_len,
const guchar *key, gint key_len)
{
SMD5 *md5;
md5 = md5_hmac_get(text, text_len, key, key_len);
memcpy(digest, s_gnet_md5_get_digest(md5), S_GNET_MD5_HASH_LENGTH);
s_gnet_md5_delete(md5);
}
void
md5_hex_hmac(gchar *hexdigest,
const guchar *text, gint text_len,
const guchar *key, gint key_len)
{
SMD5 *md5;
md5 = md5_hmac_get(text, text_len, key, key_len);
s_gnet_md5_copy_string(md5, hexdigest);
hexdigest[S_GNET_MD5_HASH_LENGTH * 2] = '\0';
s_gnet_md5_delete(md5);
}
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