500 lines
17 KiB
C++
500 lines
17 KiB
C++
// Copyright (c) 2018 Martyn Afford
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// Licensed under the MIT licence
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#ifndef SHA2_HPP
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#define SHA2_HPP
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#include <array>
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#include <cstdint>
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#include <cstring>
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namespace sha2 {
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template <size_t N>
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using hash_array = std::array<uint8_t, N>;
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using sha224_hash = hash_array<28>;
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using sha256_hash = hash_array<32>;
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using sha384_hash = hash_array<48>;
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using sha512_hash = hash_array<64>;
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// SHA-2 uses big-endian integers.
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inline void
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write_u32(uint8_t* dest, uint32_t x)
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{
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*dest++ = (x >> 24) & 0xff;
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*dest++ = (x >> 16) & 0xff;
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*dest++ = (x >> 8) & 0xff;
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*dest++ = (x >> 0) & 0xff;
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}
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inline void
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write_u64(uint8_t* dest, uint64_t x)
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{
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*dest++ = (x >> 56) & 0xff;
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*dest++ = (x >> 48) & 0xff;
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*dest++ = (x >> 40) & 0xff;
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*dest++ = (x >> 32) & 0xff;
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*dest++ = (x >> 24) & 0xff;
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*dest++ = (x >> 16) & 0xff;
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*dest++ = (x >> 8) & 0xff;
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*dest++ = (x >> 0) & 0xff;
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}
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inline uint32_t
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read_u32(const uint8_t* src)
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{
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return static_cast<uint32_t>((src[0] << 24) | (src[1] << 16) |
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(src[2] << 8) | src[3]);
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}
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inline uint64_t
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read_u64(const uint8_t* src)
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{
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uint64_t upper = read_u32(src);
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uint64_t lower = read_u32(src + 4);
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return ((upper & 0xffffffff) << 32) | (lower & 0xffffffff);
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}
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// A compiler-recognised implementation of rotate right that avoids the
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// undefined behaviour caused by shifting by the number of bits of the left-hand
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// type. See John Regehr's article https://blog.regehr.org/archives/1063
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inline uint32_t
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ror(uint32_t x, uint32_t n)
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{
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return (x >> n) | (x << (-n & 31));
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}
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inline uint64_t
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ror(uint64_t x, uint64_t n)
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{
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return (x >> n) | (x << (-n & 63));
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}
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// Utility function to truncate larger hashes. Assumes appropriate hash types
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// (i.e., hash_array<N>) for type T.
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template <typename T, size_t N>
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inline T
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truncate(const hash_array<N>& hash)
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{
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T result;
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memcpy(result.data(), hash.data(), sizeof(result));
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return result;
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}
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// Both sha256_impl and sha512_impl are used by sha224/sha256 and
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// sha384/sha512 respectively, avoiding duplication as only the initial hash
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// values (s) and output hash length change.
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inline sha256_hash
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sha256_impl(const uint32_t* s, const uint8_t* data, uint64_t length)
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{
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static_assert(sizeof(uint32_t) == 4, "sizeof(uint32_t) must be 4");
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static_assert(sizeof(uint64_t) == 8, "sizeof(uint64_t) must be 8");
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constexpr size_t chunk_bytes = 64;
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const uint64_t bit_length = length * 8;
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uint32_t hash[8] = {s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7]};
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constexpr uint32_t k[64] = {
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0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
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0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
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0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
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0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
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0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
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0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
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0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
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0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
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0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
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0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
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0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};
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auto chunk = [&hash, &k](const uint8_t* chunk_data) {
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uint32_t w[64] = {0};
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for (int i = 0; i != 16; ++i) {
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w[i] = read_u32(&chunk_data[i * 4]);
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}
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for (int i = 16; i != 64; ++i) {
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auto w15 = w[i - 15];
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auto w2 = w[i - 2];
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auto s0 = ror(w15, 7) ^ ror(w15, 18) ^ (w15 >> 3);
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auto s1 = ror(w2, 17) ^ ror(w2, 19) ^ (w2 >> 10);
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w[i] = w[i - 16] + s0 + w[i - 7] + s1;
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}
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auto a = hash[0];
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auto b = hash[1];
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auto c = hash[2];
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auto d = hash[3];
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auto e = hash[4];
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auto f = hash[5];
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auto g = hash[6];
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auto h = hash[7];
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for (int i = 0; i != 64; ++i) {
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auto s1 = ror(e, 6) ^ ror(e, 11) ^ ror(e, 25);
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auto ch = (e & f) ^ (~e & g);
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auto temp1 = h + s1 + ch + k[i] + w[i];
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auto s0 = ror(a, 2) ^ ror(a, 13) ^ ror(a, 22);
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auto maj = (a & b) ^ (a & c) ^ (b & c);
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auto temp2 = s0 + maj;
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h = g;
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g = f;
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f = e;
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e = d + temp1;
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d = c;
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c = b;
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b = a;
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a = temp1 + temp2;
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}
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hash[0] += a;
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hash[1] += b;
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hash[2] += c;
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hash[3] += d;
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hash[4] += e;
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hash[5] += f;
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hash[6] += g;
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hash[7] += h;
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};
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while (length >= chunk_bytes) {
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chunk(data);
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data += chunk_bytes;
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length -= chunk_bytes;
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}
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{
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std::array<uint8_t, chunk_bytes> buf;
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memcpy(buf.data(), data, length);
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auto i = length;
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buf[i++] = 0x80;
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if (i > chunk_bytes - 8) {
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while (i < chunk_bytes) {
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buf[i++] = 0;
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}
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chunk(buf.data());
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i = 0;
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}
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while (i < chunk_bytes - 8) {
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buf[i++] = 0;
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}
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write_u64(&buf[i], bit_length);
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chunk(buf.data());
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}
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sha256_hash result;
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for (uint8_t i = 0; i != 8; ++i) {
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write_u32(&result[i * 4], hash[i]);
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}
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return result;
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}
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inline sha512_hash
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sha512_impl(const uint64_t* s, const uint8_t* data, uint64_t length)
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{
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static_assert(sizeof(uint32_t) == 4, "sizeof(uint32_t) must be 4");
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static_assert(sizeof(uint64_t) == 8, "sizeof(uint64_t) must be 8");
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constexpr size_t chunk_bytes = 128;
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const uint64_t bit_length_low = length << 3;
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const uint64_t bit_length_high = length >> (64 - 3);
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uint64_t hash[8] = {s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7]};
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constexpr uint64_t k[80] = {
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0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f,
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0xe9b5dba58189dbbc, 0x3956c25bf348b538, 0x59f111f1b605d019,
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0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242,
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0x12835b0145706fbe, 0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2,
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0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235,
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0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3,
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0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65, 0x2de92c6f592b0275,
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0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5,
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0x983e5152ee66dfab, 0xa831c66d2db43210, 0xb00327c898fb213f,
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0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725,
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0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc,
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0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed, 0x53380d139d95b3df,
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0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6,
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0x92722c851482353b, 0xa2bfe8a14cf10364, 0xa81a664bbc423001,
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0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218,
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0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8,
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0x19a4c116b8d2d0c8, 0x1e376c085141ab53, 0x2748774cdf8eeb99,
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0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb,
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0x5b9cca4f7763e373, 0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc,
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0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec,
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0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915,
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0xc67178f2e372532b, 0xca273eceea26619c, 0xd186b8c721c0c207,
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0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba,
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0x0a637dc5a2c898a6, 0x113f9804bef90dae, 0x1b710b35131c471b,
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0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc,
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0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a,
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0x5fcb6fab3ad6faec, 0x6c44198c4a475817};
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auto chunk = [&hash, &k](const uint8_t* chunk_data) {
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uint64_t w[80] = {0};
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for (int i = 0; i != 16; ++i) {
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w[i] = read_u64(&chunk_data[i * 8]);
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}
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for (int i = 16; i != 80; ++i) {
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auto w15 = w[i - 15];
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auto w2 = w[i - 2];
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auto s0 = ror(w15, 1) ^ ror(w15, 8) ^ (w15 >> 7);
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auto s1 = ror(w2, 19) ^ ror(w2, 61) ^ (w2 >> 6);
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w[i] = w[i - 16] + s0 + w[i - 7] + s1;
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}
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auto a = hash[0];
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auto b = hash[1];
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auto c = hash[2];
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auto d = hash[3];
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auto e = hash[4];
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auto f = hash[5];
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auto g = hash[6];
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auto h = hash[7];
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for (int i = 0; i != 80; ++i) {
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auto s1 = ror(e, 14) ^ ror(e, 18) ^ ror(e, 41);
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auto ch = (e & f) ^ (~e & g);
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auto temp1 = h + s1 + ch + k[i] + w[i];
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auto s0 = ror(a, 28) ^ ror(a, 34) ^ ror(a, 39);
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auto maj = (a & b) ^ (a & c) ^ (b & c);
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auto temp2 = s0 + maj;
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h = g;
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g = f;
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f = e;
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e = d + temp1;
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d = c;
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c = b;
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b = a;
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a = temp1 + temp2;
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}
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hash[0] += a;
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hash[1] += b;
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hash[2] += c;
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hash[3] += d;
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hash[4] += e;
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hash[5] += f;
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hash[6] += g;
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hash[7] += h;
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};
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while (length >= chunk_bytes) {
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chunk(data);
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data += chunk_bytes;
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length -= chunk_bytes;
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}
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{
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std::array<uint8_t, chunk_bytes> buf;
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memcpy(buf.data(), data, length);
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auto i = length;
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buf[i++] = 0x80;
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if (i > chunk_bytes - 16) {
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while (i < chunk_bytes) {
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buf[i++] = 0;
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}
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chunk(buf.data());
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i = 0;
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}
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while (i < chunk_bytes - 16) {
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buf[i++] = 0;
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}
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write_u64(&buf[i + 0], bit_length_high);
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write_u64(&buf[i + 8], bit_length_low);
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chunk(buf.data());
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}
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sha512_hash result;
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for (uint8_t i = 0; i != 8; ++i) {
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write_u64(&result[i * 8], hash[i]);
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}
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return result;
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}
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inline sha224_hash
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sha224(const uint8_t* data, uint64_t length)
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{
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// Second 32 bits of the fractional parts of the square roots of the ninth
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// through sixteenth primes 23..53
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const uint32_t initial_hash_values[8] = {0xc1059ed8,
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0x367cd507,
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0x3070dd17,
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0xf70e5939,
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0xffc00b31,
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0x68581511,
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0x64f98fa7,
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0xbefa4fa4};
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auto hash = sha256_impl(initial_hash_values, data, length);
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return truncate<sha224_hash>(hash);
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}
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inline sha256_hash
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sha256(const uint8_t* data, uint64_t length)
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{
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// First 32 bits of the fractional parts of the square roots of the first
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// eight primes 2..19:
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const uint32_t initial_hash_values[8] = {0x6a09e667,
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0xbb67ae85,
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0x3c6ef372,
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0xa54ff53a,
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0x510e527f,
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0x9b05688c,
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0x1f83d9ab,
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0x5be0cd19};
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return sha256_impl(initial_hash_values, data, length);
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}
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inline sha384_hash
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sha384(const uint8_t* data, uint64_t length)
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{
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const uint64_t initial_hash_values[8] = {0xcbbb9d5dc1059ed8,
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0x629a292a367cd507,
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0x9159015a3070dd17,
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0x152fecd8f70e5939,
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0x67332667ffc00b31,
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0x8eb44a8768581511,
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0xdb0c2e0d64f98fa7,
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0x47b5481dbefa4fa4};
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auto hash = sha512_impl(initial_hash_values, data, length);
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return truncate<sha384_hash>(hash);
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}
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inline sha512_hash
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sha512(const uint8_t* data, uint64_t length)
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{
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const uint64_t initial_hash_values[8] = {0x6a09e667f3bcc908,
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0xbb67ae8584caa73b,
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0x3c6ef372fe94f82b,
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0xa54ff53a5f1d36f1,
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0x510e527fade682d1,
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0x9b05688c2b3e6c1f,
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0x1f83d9abfb41bd6b,
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0x5be0cd19137e2179};
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return sha512_impl(initial_hash_values, data, length);
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}
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// SHA-512/t is a truncated version of SHA-512, where the result is truncated
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// to t bits (in this implementation, t must be a multiple of eight). The two
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// primariy variants of this are SHA-512/224 and SHA-512/256, both of which are
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// provided through explicit functions (sha512_224 and sha512_256) below this
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// function. On 64-bit platforms, SHA-512, and correspondingly SHA-512/t,
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// should give a significant performance improvement over SHA-224 and SHA-256
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// due to the doubled block size.
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template <int bits>
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inline hash_array<bits / 8>
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sha512_t(const uint8_t* data, uint64_t length)
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{
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static_assert(bits % 8 == 0, "Bits must be a multiple of 8 (i.e., bytes).");
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static_assert(0 < bits && bits <= 512, "Bits must be between 8 and 512");
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static_assert(bits != 384, "NIST explicitly denies 384 bits, use SHA-384.");
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const uint64_t modified_initial_hash_values[8] = {
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0x6a09e667f3bcc908 ^ 0xa5a5a5a5a5a5a5a5,
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0xbb67ae8584caa73b ^ 0xa5a5a5a5a5a5a5a5,
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0x3c6ef372fe94f82b ^ 0xa5a5a5a5a5a5a5a5,
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0xa54ff53a5f1d36f1 ^ 0xa5a5a5a5a5a5a5a5,
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0x510e527fade682d1 ^ 0xa5a5a5a5a5a5a5a5,
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0x9b05688c2b3e6c1f ^ 0xa5a5a5a5a5a5a5a5,
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0x1f83d9abfb41bd6b ^ 0xa5a5a5a5a5a5a5a5,
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0x5be0cd19137e2179 ^ 0xa5a5a5a5a5a5a5a5};
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// The SHA-512/t generation function uses a modified SHA-512 on the string
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// "SHA-512/t" where t is the number of bits. The modified SHA-512 operates
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// like the original but uses different initial hash values, as seen above.
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// The hash is then used for the initial hash values sent to the original
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// SHA-512. The sha512_224 and sha512_256 functions have this precalculated.
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constexpr int buf_size = 12;
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uint8_t buf[buf_size];
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|
|
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auto buf_ptr = reinterpret_cast<char*>(buf);
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auto len = snprintf(buf_ptr, buf_size, "SHA-512/%d", bits);
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auto ulen = static_cast<uint64_t>(len);
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|
|
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auto initial8 = sha512_impl(modified_initial_hash_values, buf, ulen);
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|
|
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// To read the hash bytes back into 64-bit integers, we must convert back
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// from big-endian.
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uint64_t initial64[8];
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|
|
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for (uint8_t i = 0; i != 8; ++i) {
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initial64[i] = read_u64(&initial8[i * 8]);
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|
}
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|
|
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// Once the initial hash is computed, use regular SHA-512 and copy the
|
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// appropriate number of bytes.
|
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auto hash = sha512_impl(initial64, data, length);
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return truncate<hash_array<bits / 8>>(hash);
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}
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|
|
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// It is preferable to use either sha512_224 or sha512_256 in place of
|
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// sha512_t<224> or sha512_t<256> for better performance (as the initial
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|
// hashes are precalculated), for slightly less syntactic noise and for
|
|
// consistency with the other functions.
|
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inline sha224_hash
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sha512_224(const uint8_t* data, uint64_t length)
|
|
{
|
|
// Precalculated initial hash (The hash of "SHA-512/224" using the modified
|
|
// SHA-512 generation function, described above in sha512_t).
|
|
const uint64_t initial_hash_values[8] = {0x8c3d37c819544da2,
|
|
0x73e1996689dcd4d6,
|
|
0x1dfab7ae32ff9c82,
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|
0x679dd514582f9fcf,
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|
0x0f6d2b697bd44da8,
|
|
0x77e36f7304c48942,
|
|
0x3f9d85a86a1d36c8,
|
|
0x1112e6ad91d692a1};
|
|
|
|
auto hash = sha512_impl(initial_hash_values, data, length);
|
|
return truncate<sha224_hash>(hash);
|
|
}
|
|
|
|
inline sha256_hash
|
|
sha512_256(const uint8_t* data, uint64_t length)
|
|
{
|
|
// Precalculated initial hash (The hash of "SHA-512/256" using the modified
|
|
// SHA-512 generation function, described above in sha512_t).
|
|
const uint64_t initial_hash_values[8] = {0x22312194fc2bf72c,
|
|
0x9f555fa3c84c64c2,
|
|
0x2393b86b6f53b151,
|
|
0x963877195940eabd,
|
|
0x96283ee2a88effe3,
|
|
0xbe5e1e2553863992,
|
|
0x2b0199fc2c85b8aa,
|
|
0x0eb72ddc81c52ca2};
|
|
|
|
auto hash = sha512_impl(initial_hash_values, data, length);
|
|
return truncate<sha256_hash>(hash);
|
|
}
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|
|
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} // sha2 namespace
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#endif /* SHA2_HPP */
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