1  // Copyright (c) 2013-present 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 <hash.h>
 6  #include <span.h>
 7  #include <crypto/common.h>
 8  #include <crypto/hmac_sha512.h>
 9  
10  #include <bit>
11  #include <string>
12  
13  unsigned int MurmurHash3(unsigned int nHashSeed, std::span<const unsigned char> vDataToHash)
14  {
15      // The following is MurmurHash3 (x86_32), see https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp
16      uint32_t h1 = nHashSeed;
17      const uint32_t c1 = 0xcc9e2d51;
18      const uint32_t c2 = 0x1b873593;
19  
20      const int nblocks = vDataToHash.size() / 4;
21  
22      //----------
23      // body
24      const uint8_t* blocks = vDataToHash.data();
25  
26      for (int i = 0; i < nblocks; ++i) {
27          uint32_t k1 = ReadLE32(blocks + i*4);
28  
29          k1 *= c1;
30          k1 = std::rotl(k1, 15);
31          k1 *= c2;
32  
33          h1 ^= k1;
34          h1 = std::rotl(h1, 13);
35          h1 = h1 * 5 + 0xe6546b64;
36      }
37  
38      //----------
39      // tail
40      const uint8_t* tail = vDataToHash.data() + nblocks * 4;
41  
42      uint32_t k1 = 0;
43  
44      switch (vDataToHash.size() & 3) {
45          case 3:
46              k1 ^= tail[2] << 16;
47              [[fallthrough]];
48          case 2:
49              k1 ^= tail[1] << 8;
50              [[fallthrough]];
51          case 1:
52              k1 ^= tail[0];
53              k1 *= c1;
54              k1 = std::rotl(k1, 15);
55              k1 *= c2;
56              h1 ^= k1;
57      }
58  
59      //----------
60      // finalization
61      h1 ^= vDataToHash.size();
62      h1 ^= h1 >> 16;
63      h1 *= 0x85ebca6b;
64      h1 ^= h1 >> 13;
65      h1 *= 0xc2b2ae35;
66      h1 ^= h1 >> 16;
67  
68      return h1;
69  }
70  
71  void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64])
72  {
73      unsigned char num[4];
74      WriteBE32(num, nChild);
75      CHMAC_SHA512(chainCode.begin(), chainCode.size()).Write(&header, 1).Write(data, 32).Write(num, 4).Finalize(output);
76  }
77  
78  uint256 SHA256Uint256(const uint256& input)
79  {
80      uint256 result;
81      CSHA256().Write(input.begin(), 32).Finalize(result.begin());
82      return result;
83  }
84  
85  HashWriter TaggedHash(const std::string& tag)
86  {
87      HashWriter writer{};
88      uint256 taghash;
89      CSHA256().Write((const unsigned char*)tag.data(), tag.size()).Finalize(taghash.begin());
90      writer << taghash << taghash;
91      return writer;
92  }