1  // Copyright (c) 2014-2018 The Bitcoin Core developers
 2  // Distributed under the MIT software license, see the accompanying
 3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 4  
 5  #include <crypto/hmac_sha256.h>
 6  
 7  #include <string.h>
 8  
 9  CHMAC_SHA256::CHMAC_SHA256(const unsigned char* key, size_t keylen)
10  {
11      unsigned char rkey[64];
12      if (keylen <= 64) {
13          memcpy(rkey, key, keylen);
14          memset(rkey + keylen, 0, 64 - keylen);
15      } else {
16          CSHA256().Write(key, keylen).Finalize(rkey);
17          memset(rkey + 32, 0, 32);
18      }
19  
20      for (int n = 0; n < 64; n++)
21          rkey[n] ^= 0x5c;
22      outer.Write(rkey, 64);
23  
24      for (int n = 0; n < 64; n++)
25          rkey[n] ^= 0x5c ^ 0x36;
26      inner.Write(rkey, 64);
27  }
28  
29  void CHMAC_SHA256::Finalize(unsigned char hash[OUTPUT_SIZE])
30  {
31      unsigned char temp[32];
32      inner.Finalize(temp);
33      outer.Write(temp, 32).Finalize(hash);
34  }