Bitcoin Core  27.99.0
P2P Digital Currency
hash.cpp
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1 // Copyright (c) 2013-2022 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, 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 
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 }
A hasher class for HMAC-SHA-512.
Definition: hmac_sha512.h:15
void Finalize(unsigned char hash[OUTPUT_SIZE])
Definition: hmac_sha512.cpp:29
CHMAC_SHA512 & Write(const unsigned char *data, size_t len)
Definition: hmac_sha512.h:24
A hasher class for SHA-256.
Definition: sha256.h:14
void Finalize(unsigned char hash[OUTPUT_SIZE])
Definition: sha256.cpp:726
CSHA256 & Write(const unsigned char *data, size_t len)
Definition: sha256.cpp:700
A writer stream (for serialization) that computes a 256-bit hash.
Definition: hash.h:101
constexpr std::size_t size() const noexcept
Definition: span.h:187
constexpr C * data() const noexcept
Definition: span.h:174
static constexpr unsigned int size()
Definition: uint256.h:74
constexpr unsigned char * begin()
Definition: uint256.h:68
256-bit opaque blob.
Definition: uint256.h:106
static uint32_t ReadLE32(const unsigned char *ptr)
Definition: common.h:20
static void WriteBE32(unsigned char *ptr, uint32_t x)
Definition: common.h:73
void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64])
Definition: hash.cpp:71
unsigned int MurmurHash3(unsigned int nHashSeed, Span< const unsigned char > vDataToHash)
Definition: hash.cpp:13
HashWriter TaggedHash(const std::string &tag)
Return a HashWriter primed for tagged hashes (as specified in BIP 340).
Definition: hash.cpp:85
uint256 SHA256Uint256(const uint256 &input)
Single-SHA256 a 32-byte input (represented as uint256).
Definition: hash.cpp:78
static SECP256K1_INLINE uint64_t rotl(const uint64_t x, int k)
Definition: testrand_impl.h:39