// SPDX-FileCopyrightText: 2019-2024 Connor McLaughlin // SPDX-License-Identifier: CC-BY-NC-ND-4.0 // Based on https://github.com/B-Con/crypto-algorithms/blob/master/sha256.c // By Brad Conte (brad AT bradconte.com) #include "sha256_digest.h" #include "string_util.h" #include SHA256Digest::SHA256Digest() { Reset(); } std::string SHA256Digest::DigestToString(const std::span digest) { return StringUtil::EncodeHex(digest); } SHA256Digest::Digest SHA256Digest::GetDigest(const void* data, size_t len) { Digest ret; SHA256Digest digest; digest.Update(data, len); digest.Final(ret); return ret; } SHA256Digest::Digest SHA256Digest::GetDigest(std::span data) { Digest ret; SHA256Digest digest; digest.Update(data); digest.Final(ret); return ret; } #define ROTLEFT(a, b) (((a) << (b)) | ((a) >> (32 - (b)))) #define ROTRIGHT(a, b) (((a) >> (b)) | ((a) << (32 - (b)))) #define CH(x, y, z) (((x) & (y)) ^ (~(x) & (z))) #define MAJ(x, y, z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z))) #define EP0(x) (ROTRIGHT(x, 2) ^ ROTRIGHT(x, 13) ^ ROTRIGHT(x, 22)) #define EP1(x) (ROTRIGHT(x, 6) ^ ROTRIGHT(x, 11) ^ ROTRIGHT(x, 25)) #define SIG0(x) (ROTRIGHT(x, 7) ^ ROTRIGHT(x, 18) ^ ((x) >> 3)) #define SIG1(x) (ROTRIGHT(x, 17) ^ ROTRIGHT(x, 19) ^ ((x) >> 10)) static constexpr std::array k = { {0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2}}; void SHA256Digest::TransformBlock() { std::array m; size_t i = 0; for (size_t j = 0; i < 16; ++i, j += 4) m[i] = (m_block[j] << 24) | (m_block[j + 1] << 16) | (m_block[j + 2] << 8) | (m_block[j + 3]); for (; i < 64; ++i) m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16]; u32 a = m_state[0]; u32 b = m_state[1]; u32 c = m_state[2]; u32 d = m_state[3]; u32 e = m_state[4]; u32 f = m_state[5]; u32 g = m_state[6]; u32 h = m_state[7]; for (i = 0; i < 64; ++i) { u32 t1 = h + EP1(e) + CH(e, f, g) + k[i] + m[i]; u32 t2 = EP0(a) + MAJ(a, b, c); h = g; g = f; f = e; e = d + t1; d = c; c = b; b = a; a = t1 + t2; } m_state[0] += a; m_state[1] += b; m_state[2] += c; m_state[3] += d; m_state[4] += e; m_state[5] += f; m_state[6] += g; m_state[7] += h; } void SHA256Digest::Reset() { m_block_length = 0; m_bit_length = 0; m_state[0] = 0x6a09e667; m_state[1] = 0xbb67ae85; m_state[2] = 0x3c6ef372; m_state[3] = 0xa54ff53a; m_state[4] = 0x510e527f; m_state[5] = 0x9b05688c; m_state[6] = 0x1f83d9ab; m_state[7] = 0x5be0cd19; } void SHA256Digest::Update(std::span data) { const size_t len = data.size(); for (size_t pos = 0; pos < len;) { const u32 copy_len = static_cast(std::min(len - pos, BLOCK_SIZE - m_block_length)); std::memcpy(&m_block[m_block_length], &data[pos], copy_len); m_block_length += copy_len; pos += copy_len; if (m_block_length == BLOCK_SIZE) { TransformBlock(); m_bit_length += 512; m_block_length = 0; } } } void SHA256Digest::Update(const void* data, size_t len) { Update(std::span(static_cast(data), len)); } void SHA256Digest::Final(std::span digest) { // Pad whatever data is left in the buffer. if (m_block_length < 56) { size_t i = m_block_length; m_block[i++] = 0x80; while (i < 56) m_block[i++] = 0x00; } else { size_t i = m_block_length; m_block[i++] = 0x80; while (i < 64) m_block[i++] = 0x00; TransformBlock(); m_block = {}; } // Append to the padding the total message's length in bits and transform. m_bit_length += m_block_length * 8; m_block[63] = static_cast(m_bit_length); m_block[62] = static_cast(m_bit_length >> 8); m_block[61] = static_cast(m_bit_length >> 16); m_block[60] = static_cast(m_bit_length >> 24); m_block[59] = static_cast(m_bit_length >> 32); m_block[58] = static_cast(m_bit_length >> 40); m_block[57] = static_cast(m_bit_length >> 48); m_block[56] = static_cast(m_bit_length >> 56); TransformBlock(); // Since this implementation uses little endian byte ordering and SHA uses big endian, // reverse all the bytes when copying the final state to the output hash. for (size_t i = 0; i < 4; ++i) { digest[i] = (m_state[0] >> (24 - i * 8)) & 0x000000ff; digest[i + 4] = (m_state[1] >> (24 - i * 8)) & 0x000000ff; digest[i + 8] = (m_state[2] >> (24 - i * 8)) & 0x000000ff; digest[i + 12] = (m_state[3] >> (24 - i * 8)) & 0x000000ff; digest[i + 16] = (m_state[4] >> (24 - i * 8)) & 0x000000ff; digest[i + 20] = (m_state[5] >> (24 - i * 8)) & 0x000000ff; digest[i + 24] = (m_state[6] >> (24 - i * 8)) & 0x000000ff; digest[i + 28] = (m_state[7] >> (24 - i * 8)) & 0x000000ff; } } SHA256Digest::Digest SHA256Digest::Final() { Digest ret; Final(ret); return ret; }