1  // Copyright (c) 2014-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  #ifndef BITCOIN_CRYPTO_SHA256_H
 6  #define BITCOIN_CRYPTO_SHA256_H
 7  
 8  #include <cstdint>
 9  #include <cstdlib>
10  #include <string>
11  
12  /** A hasher class for SHA-256. */
13  class CSHA256
14  {
15  private:
16      uint32_t s[8];
17      unsigned char buf[64];
18      uint64_t bytes{0};
19  
20  public:
21      static const size_t OUTPUT_SIZE = 32;
22  
23      CSHA256();
24      CSHA256& Write(const unsigned char* data, size_t len);
25      void Finalize(unsigned char hash[OUTPUT_SIZE]);
26      CSHA256& Reset();
27  };
28  
29  namespace sha256_implementation {
30  enum UseImplementation : uint8_t {
31      STANDARD = 0,
32      USE_SSE4 = 1 << 0,
33      USE_AVX2 = 1 << 1,
34      USE_SHANI = 1 << 2,
35      USE_SSE4_AND_AVX2 = USE_SSE4 | USE_AVX2,
36      USE_SSE4_AND_SHANI = USE_SSE4 | USE_SHANI,
37      USE_ALL = USE_SSE4 | USE_AVX2 | USE_SHANI,
38  };
39  }
40  
41  /** Autodetect the best available SHA256 implementation.
42   *  Returns the name of the implementation.
43   */
44  std::string SHA256AutoDetect(sha256_implementation::UseImplementation use_implementation = sha256_implementation::USE_ALL);
45  
46  /** Compute multiple double-SHA256's of 64-byte blobs.
47   *  output:  pointer to a blocks*32 byte output buffer
48   *  input:   pointer to a blocks*64 byte input buffer
49   *  blocks:  the number of hashes to compute.
50   */
51  void SHA256D64(unsigned char* output, const unsigned char* input, size_t blocks);
52  
53  #endif // BITCOIN_CRYPTO_SHA256_H