ZeroTierOne/node/HMAC.cpp

82 lines
2.4 KiB
C++

/*
* ZeroTier One - Global Peer to Peer Ethernet
* Copyright (C) 2012-2013 ZeroTier Networks LLC
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
* --
*
* ZeroTier may be used and distributed under the terms of the GPLv3, which
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
*
* If you would like to embed ZeroTier into a commercial application or
* redistribute it in a modified binary form, please contact ZeroTier Networks
* LLC. Start here: http://www.zerotier.com/
*/
#include "HMAC.hpp"
#include <openssl/sha.h>
namespace ZeroTier {
void HMAC::sha256(const void *key,unsigned int klen,const void *message,unsigned int len,void *mac)
throw()
{
union {
uint64_t q[12];
uint8_t b[96];
} key2,opad,ipad;
SHA256_CTX sha;
if (klen == 32) { // this is what we use, so handle this quickly
key2.q[0] = ((const uint64_t *)key)[0];
key2.q[1] = ((const uint64_t *)key)[1];
key2.q[2] = ((const uint64_t *)key)[2];
key2.q[3] = ((const uint64_t *)key)[3];
key2.q[4] = 0ULL;
key2.q[5] = 0ULL;
key2.q[6] = 0ULL;
key2.q[7] = 0ULL;
} else { // for correctness and testing against test vectors
if (klen > 64) {
SHA256_Init(&sha);
SHA256_Update(&sha,key,klen);
SHA256_Final(key2.b,&sha);
klen = 32;
} else {
for(unsigned int i=0;i<klen;++i)
key2.b[i] = ((const uint8_t *)key)[i];
}
while (klen < 64)
key2.b[klen++] = (uint8_t)0;
}
for(unsigned int i=0;i<8;++i)
opad.q[i] = 0x5c5c5c5c5c5c5c5cULL ^ key2.q[i];
for(unsigned int i=0;i<8;++i)
ipad.q[i] = 0x3636363636363636ULL ^ key2.q[i];
SHA256_Init(&sha);
SHA256_Update(&sha,(const unsigned char *)ipad.b,64);
SHA256_Update(&sha,(const unsigned char *)message,len);
SHA256_Final((unsigned char *)(opad.b + 64),&sha);
SHA256_Init(&sha);
SHA256_Update(&sha,opad.b,96);
SHA256_Final((unsigned char *)mac,&sha);
}
} // namespace ZeroTier