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 <cstddef>
9#include <cstdint>
10#include <string>
11
12/** A hasher class for SHA-256. */
13class CSHA256
14{
15private:
16    uint32_t s[8];
17    unsigned char buf[64];
18    uint64_t bytes{0};
19
20public:
21    static constexpr 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
29namespace sha256_implementation {
30enum 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 */
44std::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 */
51void SHA256D64(unsigned char* output, const unsigned char* input, size_t blocks);
52
53#endif // BITCOIN_CRYPTO_SHA256_H
54