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//
// VMime library (http://vmime.sourceforge.net)
// Copyright (C) 2002-2004 Vincent Richard <[email protected]>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// This program 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
#include "authHelper.hpp"
#include "../config.hpp"
#include "../utility/md5.hpp"
namespace vmime {
namespace messaging {
//
// This code is based on the Sample Code published in the Appendix of
// the RFC-2104: "HMAC: Keyed-Hashing for Message Authentication".
//
void hmac_md5(const string& text, const string& key, string& hexDigest)
{
vmime_uint8 digest[16];
unsigned char ipad[65]; // inner padding - key XORd with ipad
unsigned char opad[65]; // outer padding - key XORd with opad
unsigned char tkey[16];
int tkeyLen;
// If key is longer than 64 bytes reset it to key = MD5(key)
if (key.length() > 64)
{
utility::md5 keyMD5;
keyMD5.update((vmime_uint8*) key.data(), key.length());
std::copy(keyMD5.hash(), keyMD5.hash() + 16, tkey);
tkeyLen = 16;
}
else
{
std::copy(key.begin(), key.end(), tkey);
tkeyLen = key.length();
}
//
// 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
//
// Start out by storing key in pads
std::fill(ipad, ipad + sizeof(ipad), 0);
std::fill(opad, opad + sizeof(opad), 0);
std::copy(tkey, tkey + tkeyLen, ipad);
std::copy(tkey, tkey + tkeyLen, opad);
// XOR key with ipad and opad values
for (int i = 0 ; i < 64 ; ++i)
{
ipad[i] ^= 0x36;
opad[i] ^= 0x5c;
}
// Perform inner MD5
utility::md5 innerMD5;
innerMD5.update(ipad, 64);
innerMD5.update(text);
std::copy(innerMD5.hash(), innerMD5.hash() + 16, digest);
// Perform outer MD5
utility::md5 outerMD5;
outerMD5.update(opad, 64);
outerMD5.update(digest, 16);
//std::copy(outerMD5.hash(), outerMD5.hash() + 16, digest);
hexDigest = outerMD5.hex();
}
} // messaging
} // vmime
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