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
13unsigned 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
71void 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
78uint256 SHA256Uint256(const uint256& input)
79{
80    uint256 result;
81    CSHA256().Write(input.begin(), 32).Finalize(result.begin());
82    return result;
83}
84
85HashWriter 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}
93