sha256.cpp

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// Copyright (c) 2014-2017 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <crypto/sha256.h>
#include <crypto/common.h>

#include <assert.h>
#include <string.h>
#include <atomic>

#if defined(__x86_64__) || defined(__amd64__)
#if defined(USE_ASM)
#include <cpuid.h>
namespace sha256_sse4
{
void Transform(uint32_t* s, const unsigned char* chunk, size_t blocks);
}
#endif
#endif

// Internal implementation code.
namespace
{
namespace sha256
{
uint32_t inline Ch(uint32_t x, uint32_t y, uint32_t z) { return z ^ (x & (y ^ z)); }
uint32_t inline Maj(uint32_t x, uint32_t y, uint32_t z) { return (x & y) | (z & (x | y)); }
uint32_t inline Sigma0(uint32_t x) { return (x >> 2 | x << 30) ^ (x >> 13 | x << 19) ^ (x >> 22 | x << 10); }
uint32_t inline Sigma1(uint32_t x) { return (x >> 6 | x << 26) ^ (x >> 11 | x << 21) ^ (x >> 25 | x << 7); }
uint32_t inline sigma0(uint32_t x) { return (x >> 7 | x << 25) ^ (x >> 18 | x << 14) ^ (x >> 3); }
uint32_t inline sigma1(uint32_t x) { return (x >> 17 | x << 15) ^ (x >> 19 | x << 13) ^ (x >> 10); }

void inline Round(uint32_t a, uint32_t b, uint32_t c, uint32_t& d, uint32_t e, uint32_t f, uint32_t g, uint32_t& h, uint32_t k, uint32_t w)
{
    uint32_t t1 = h + Sigma1(e) + Ch(e, f, g) + k + w;
    uint32_t t2 = Sigma0(a) + Maj(a, b, c);
    d += t1;
    h = t1 + t2;
}

void inline Initialize(uint32_t* s)
{
    s[0] = 0x6a09e667ul;
    s[1] = 0xbb67ae85ul;
    s[2] = 0x3c6ef372ul;
    s[3] = 0xa54ff53aul;
    s[4] = 0x510e527ful;
    s[5] = 0x9b05688cul;
    s[6] = 0x1f83d9abul;
    s[7] = 0x5be0cd19ul;
}

void Transform(uint32_t* s, const unsigned char* chunk, size_t blocks)
{
    while (blocks--) {
        uint32_t a = s[0], b = s[1], c = s[2], d = s[3], e = s[4], f = s[5], g = s[6], h = s[7];
        uint32_t w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;

        Round(a, b, c, d, e, f, g, h, 0x428a2f98, w0 = ReadBE32(chunk + 0));
        Round(h, a, b, c, d, e, f, g, 0x71374491, w1 = ReadBE32(chunk + 4));
        Round(g, h, a, b, c, d, e, f, 0xb5c0fbcf, w2 = ReadBE32(chunk + 8));
        Round(f, g, h, a, b, c, d, e, 0xe9b5dba5, w3 = ReadBE32(chunk + 12));
        Round(e, f, g, h, a, b, c, d, 0x3956c25b, w4 = ReadBE32(chunk + 16));
        Round(d, e, f, g, h, a, b, c, 0x59f111f1, w5 = ReadBE32(chunk + 20));
        Round(c, d, e, f, g, h, a, b, 0x923f82a4, w6 = ReadBE32(chunk + 24));
        Round(b, c, d, e, f, g, h, a, 0xab1c5ed5, w7 = ReadBE32(chunk + 28));
        Round(a, b, c, d, e, f, g, h, 0xd807aa98, w8 = ReadBE32(chunk + 32));
        Round(h, a, b, c, d, e, f, g, 0x12835b01, w9 = ReadBE32(chunk + 36));
        Round(g, h, a, b, c, d, e, f, 0x243185be, w10 = ReadBE32(chunk + 40));
        Round(f, g, h, a, b, c, d, e, 0x550c7dc3, w11 = ReadBE32(chunk + 44));
        Round(e, f, g, h, a, b, c, d, 0x72be5d74, w12 = ReadBE32(chunk + 48));
        Round(d, e, f, g, h, a, b, c, 0x80deb1fe, w13 = ReadBE32(chunk + 52));
        Round(c, d, e, f, g, h, a, b, 0x9bdc06a7, w14 = ReadBE32(chunk + 56));
        Round(b, c, d, e, f, g, h, a, 0xc19bf174, w15 = ReadBE32(chunk + 60));

        Round(a, b, c, d, e, f, g, h, 0xe49b69c1, w0 += sigma1(w14) + w9 + sigma0(w1));
        Round(h, a, b, c, d, e, f, g, 0xefbe4786, w1 += sigma1(w15) + w10 + sigma0(w2));
        Round(g, h, a, b, c, d, e, f, 0x0fc19dc6, w2 += sigma1(w0) + w11 + sigma0(w3));
        Round(f, g, h, a, b, c, d, e, 0x240ca1cc, w3 += sigma1(w1) + w12 + sigma0(w4));
        Round(e, f, g, h, a, b, c, d, 0x2de92c6f, w4 += sigma1(w2) + w13 + sigma0(w5));
        Round(d, e, f, g, h, a, b, c, 0x4a7484aa, w5 += sigma1(w3) + w14 + sigma0(w6));
        Round(c, d, e, f, g, h, a, b, 0x5cb0a9dc, w6 += sigma1(w4) + w15 + sigma0(w7));
        Round(b, c, d, e, f, g, h, a, 0x76f988da, w7 += sigma1(w5) + w0 + sigma0(w8));
        Round(a, b, c, d, e, f, g, h, 0x983e5152, w8 += sigma1(w6) + w1 + sigma0(w9));
        Round(h, a, b, c, d, e, f, g, 0xa831c66d, w9 += sigma1(w7) + w2 + sigma0(w10));
        Round(g, h, a, b, c, d, e, f, 0xb00327c8, w10 += sigma1(w8) + w3 + sigma0(w11));
        Round(f, g, h, a, b, c, d, e, 0xbf597fc7, w11 += sigma1(w9) + w4 + sigma0(w12));
        Round(e, f, g, h, a, b, c, d, 0xc6e00bf3, w12 += sigma1(w10) + w5 + sigma0(w13));
        Round(d, e, f, g, h, a, b, c, 0xd5a79147, w13 += sigma1(w11) + w6 + sigma0(w14));
        Round(c, d, e, f, g, h, a, b, 0x06ca6351, w14 += sigma1(w12) + w7 + sigma0(w15));
        Round(b, c, d, e, f, g, h, a, 0x14292967, w15 += sigma1(w13) + w8 + sigma0(w0));

        Round(a, b, c, d, e, f, g, h, 0x27b70a85, w0 += sigma1(w14) + w9 + sigma0(w1));
        Round(h, a, b, c, d, e, f, g, 0x2e1b2138, w1 += sigma1(w15) + w10 + sigma0(w2));
        Round(g, h, a, b, c, d, e, f, 0x4d2c6dfc, w2 += sigma1(w0) + w11 + sigma0(w3));
        Round(f, g, h, a, b, c, d, e, 0x53380d13, w3 += sigma1(w1) + w12 + sigma0(w4));
        Round(e, f, g, h, a, b, c, d, 0x650a7354, w4 += sigma1(w2) + w13 + sigma0(w5));
        Round(d, e, f, g, h, a, b, c, 0x766a0abb, w5 += sigma1(w3) + w14 + sigma0(w6));
        Round(c, d, e, f, g, h, a, b, 0x81c2c92e, w6 += sigma1(w4) + w15 + sigma0(w7));
        Round(b, c, d, e, f, g, h, a, 0x92722c85, w7 += sigma1(w5) + w0 + sigma0(w8));
        Round(a, b, c, d, e, f, g, h, 0xa2bfe8a1, w8 += sigma1(w6) + w1 + sigma0(w9));
        Round(h, a, b, c, d, e, f, g, 0xa81a664b, w9 += sigma1(w7) + w2 + sigma0(w10));
        Round(g, h, a, b, c, d, e, f, 0xc24b8b70, w10 += sigma1(w8) + w3 + sigma0(w11));
        Round(f, g, h, a, b, c, d, e, 0xc76c51a3, w11 += sigma1(w9) + w4 + sigma0(w12));
        Round(e, f, g, h, a, b, c, d, 0xd192e819, w12 += sigma1(w10) + w5 + sigma0(w13));
        Round(d, e, f, g, h, a, b, c, 0xd6990624, w13 += sigma1(w11) + w6 + sigma0(w14));
        Round(c, d, e, f, g, h, a, b, 0xf40e3585, w14 += sigma1(w12) + w7 + sigma0(w15));
        Round(b, c, d, e, f, g, h, a, 0x106aa070, w15 += sigma1(w13) + w8 + sigma0(w0));

        Round(a, b, c, d, e, f, g, h, 0x19a4c116, w0 += sigma1(w14) + w9 + sigma0(w1));
        Round(h, a, b, c, d, e, f, g, 0x1e376c08, w1 += sigma1(w15) + w10 + sigma0(w2));
        Round(g, h, a, b, c, d, e, f, 0x2748774c, w2 += sigma1(w0) + w11 + sigma0(w3));
        Round(f, g, h, a, b, c, d, e, 0x34b0bcb5, w3 += sigma1(w1) + w12 + sigma0(w4));
        Round(e, f, g, h, a, b, c, d, 0x391c0cb3, w4 += sigma1(w2) + w13 + sigma0(w5));
        Round(d, e, f, g, h, a, b, c, 0x4ed8aa4a, w5 += sigma1(w3) + w14 + sigma0(w6));
        Round(c, d, e, f, g, h, a, b, 0x5b9cca4f, w6 += sigma1(w4) + w15 + sigma0(w7));
        Round(b, c, d, e, f, g, h, a, 0x682e6ff3, w7 += sigma1(w5) + w0 + sigma0(w8));
        Round(a, b, c, d, e, f, g, h, 0x748f82ee, w8 += sigma1(w6) + w1 + sigma0(w9));
        Round(h, a, b, c, d, e, f, g, 0x78a5636f, w9 += sigma1(w7) + w2 + sigma0(w10));
        Round(g, h, a, b, c, d, e, f, 0x84c87814, w10 += sigma1(w8) + w3 + sigma0(w11));
        Round(f, g, h, a, b, c, d, e, 0x8cc70208, w11 += sigma1(w9) + w4 + sigma0(w12));
        Round(e, f, g, h, a, b, c, d, 0x90befffa, w12 += sigma1(w10) + w5 + sigma0(w13));
        Round(d, e, f, g, h, a, b, c, 0xa4506ceb, w13 += sigma1(w11) + w6 + sigma0(w14));
        Round(c, d, e, f, g, h, a, b, 0xbef9a3f7, w14 + sigma1(w12) + w7 + sigma0(w15));
        Round(b, c, d, e, f, g, h, a, 0xc67178f2, w15 + sigma1(w13) + w8 + sigma0(w0));

        s[0] += a;
        s[1] += b;
        s[2] += c;
        s[3] += d;
        s[4] += e;
        s[5] += f;
        s[6] += g;
        s[7] += h;
        chunk += 64;
    }
}

} // namespace sha256

typedef void (*TransformType)(uint32_t*, const unsigned char*, size_t);

bool SelfTest(TransformType tr) {
    static const unsigned char in1[65] = {0, 0x80};
    static const unsigned char in2[129] = {
        0,
        32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 
        32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 
        0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0
    };
    static const uint32_t init[8] = {0x6a09e667ul, 0xbb67ae85ul, 0x3c6ef372ul, 0xa54ff53aul, 0x510e527ful, 0x9b05688cul, 0x1f83d9abul, 0x5be0cd19ul};
    static const uint32_t out1[8] = {0xe3b0c442ul, 0x98fc1c14ul, 0x9afbf4c8ul, 0x996fb924ul, 0x27ae41e4ul, 0x649b934cul, 0xa495991bul, 0x7852b855ul};
    static const uint32_t out2[8] = {0xce4153b0ul, 0x147c2a86ul, 0x3ed4298eul, 0xe0676bc8ul, 0x79fc77a1ul, 0x2abe1f49ul, 0xb2b055dful, 0x1069523eul};
    uint32_t buf[8];
    memcpy(buf, init, sizeof(buf));
    // Process nothing, and check we remain in the initial state.
    tr(buf, nullptr, 0);
    if (memcmp(buf, init, sizeof(buf))) return false;
    // Process the padded empty string (unaligned)
    tr(buf, in1 + 1, 1);
    if (memcmp(buf, out1, sizeof(buf))) return false;
    // Process 64 spaces (unaligned)
    memcpy(buf, init, sizeof(buf));
    tr(buf, in2 + 1, 2);
    if (memcmp(buf, out2, sizeof(buf))) return false;
    return true;
}

TransformType Transform = sha256::Transform;

} // namespace

std::string SHA256AutoDetect()
{
#if defined(USE_ASM) && (defined(__x86_64__) || defined(__amd64__))
    uint32_t eax, ebx, ecx, edx;
    if (__get_cpuid(1, &eax, &ebx, &ecx, &edx) && (ecx >> 19) & 1) {
        Transform = sha256_sse4::Transform;
        assert(SelfTest(Transform));
        return "sse4";
    }
#endif

    assert(SelfTest(Transform));
    return "standard";
}


CSHA256::CSHA256() : bytes(0)
{
    sha256::Initialize(s);
}

CSHA256& CSHA256::Write(const unsigned char* data, size_t len)
{
    const unsigned char* end = data + len;
    size_t bufsize = bytes % 64;
    if (bufsize && bufsize + len >= 64) {
        // Fill the buffer, and process it.
        memcpy(buf + bufsize, data, 64 - bufsize);
        bytes += 64 - bufsize;
        data += 64 - bufsize;
        Transform(s, buf, 1);
        bufsize = 0;
    }
    if (end - data >= 64) {
        size_t blocks = (end - data) / 64;
        Transform(s, data, blocks);
        data += 64 * blocks;
        bytes += 64 * blocks;
    }
    if (end > data) {
        // Fill the buffer with what remains.
        memcpy(buf + bufsize, data, end - data);
        bytes += end - data;
    }
    return *this;
}

void CSHA256::Finalize(unsigned char hash[OUTPUT_SIZE])
{
    static const unsigned char pad[64] = {0x80};
    unsigned char sizedesc[8];
    WriteBE64(sizedesc, bytes << 3);
    Write(pad, 1 + ((119 - (bytes % 64)) % 64));
    Write(sizedesc, 8);
    WriteBE32(hash, s[0]);
    WriteBE32(hash + 4, s[1]);
    WriteBE32(hash + 8, s[2]);
    WriteBE32(hash + 12, s[3]);
    WriteBE32(hash + 16, s[4]);
    WriteBE32(hash + 20, s[5]);
    WriteBE32(hash + 24, s[6]);
    WriteBE32(hash + 28, s[7]);
}

CSHA256& CSHA256::Reset()
{
    bytes = 0;
    sha256::Initialize(s);
    return *this;
}