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// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/hash/sha1.h"
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include "base/sys_byteorder.h"
namespace base {
// Implementation of SHA-1. Only handles data in byte-sized blocks,
// which simplifies the code a fair bit.
// Identifier names follow notation in FIPS PUB 180-3, where you'll
// also find a description of the algorithm:
// http://csrc.nist.gov/publications/fips/fips180-3/fips180-3_final.pdf
// Usage example:
//
// SecureHashAlgorithm sha;
// while(there is data to hash)
// sha.Update(moredata, size of data);
// sha.Final();
// memcpy(somewhere, sha.Digest(), 20);
//
// to reuse the instance of sha, call sha.Init();
static inline uint32_t f(uint32_t t, uint32_t B, uint32_t C, uint32_t D) {
if (t < 20)
return (B & C) | ((~B) & D);
if (t < 40)
return B ^ C ^ D;
if (t < 60)
return (B & C) | (B & D) | (C & D);
return B ^ C ^ D;
}
static inline uint32_t S(uint32_t n, uint32_t X) {
return (X << n) | (X >> (32 - n));
}
static inline uint32_t K(uint32_t t) {
if (t < 20)
return 0x5a827999;
if (t < 40)
return 0x6ed9eba1;
if (t < 60)
return 0x8f1bbcdc;
return 0xca62c1d6;
}
void SHA1Context::Init() {
A = 0;
B = 0;
C = 0;
D = 0;
E = 0;
cursor = 0;
l = 0;
H[0] = 0x67452301;
H[1] = 0xefcdab89;
H[2] = 0x98badcfe;
H[3] = 0x10325476;
H[4] = 0xc3d2e1f0;
}
void SHA1Context::Update(const void* data, size_t nbytes) {
const uint8_t* d = reinterpret_cast<const uint8_t*>(data);
while (nbytes--) {
M[cursor++] = *d++;
if (cursor >= 64) {
Process();
}
l += 8;
}
}
void SHA1Context::Final() {
Pad();
Process();
for (auto& t : H) {
t = ByteSwap(t);
}
}
const unsigned char* SHA1Context::GetDigest() const {
return reinterpret_cast<const unsigned char*>(H);
}
void SHA1Context::Pad() {
M[cursor++] = 0x80;
if (cursor > 64 - 8) {
// pad out to next block
while (cursor < 64) {
M[cursor++] = 0;
}
Process();
}
while (cursor < 64 - 8) {
M[cursor++] = 0;
}
M[cursor++] = (l >> 56) & 0xff;
M[cursor++] = (l >> 48) & 0xff;
M[cursor++] = (l >> 40) & 0xff;
M[cursor++] = (l >> 32) & 0xff;
M[cursor++] = (l >> 24) & 0xff;
M[cursor++] = (l >> 16) & 0xff;
M[cursor++] = (l >> 8) & 0xff;
M[cursor++] = l & 0xff;
}
void SHA1Context::Process() {
uint32_t t;
// Each a...e corresponds to a section in the FIPS 180-3 algorithm.
// a.
//
// W and M are in a union, so no need to memcpy.
// memcpy(W, M, sizeof(M));
for (t = 0; t < 16; ++t) {
W[t] = ByteSwap(W[t]);
}
// b.
for (t = 16; t < 80; ++t) {
W[t] = S(1, W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]);
}
// c.
A = H[0];
B = H[1];
C = H[2];
D = H[3];
E = H[4];
// d.
for (t = 0; t < 80; ++t) {
uint32_t TEMP = S(5, A) + f(t, B, C, D) + E + W[t] + K(t);
E = D;
D = C;
C = S(30, B);
B = A;
A = TEMP;
}
// e.
H[0] += A;
H[1] += B;
H[2] += C;
H[3] += D;
H[4] += E;
cursor = 0;
}
// These functions allow streaming SHA-1 operations.
void SHA1Init(SHA1Context& context) {
context.Init();
}
void SHA1Update(const StringPiece data, SHA1Context& context) {
context.Update(data.data(), data.size());
}
void SHA1Final(SHA1Context& context, SHA1Digest& digest) {
context.Final();
memcpy(digest.data(), context.GetDigest(), kSHA1Length);
}
SHA1Digest SHA1HashSpan(span<const uint8_t> data) {
SHA1Digest hash;
SHA1HashBytes(data.data(), data.size(), hash.data());
return hash;
}
std::string SHA1HashString(StringPiece str) {
char hash[kSHA1Length];
SHA1HashBytes(reinterpret_cast<const unsigned char*>(str.data()),
str.length(), reinterpret_cast<unsigned char*>(hash));
return std::string(hash, kSHA1Length);
}
void SHA1HashBytes(const unsigned char* data, size_t len, unsigned char* hash) {
SHA1Context context;
context.Init();
context.Update(data, len);
context.Final();
memcpy(hash, context.GetDigest(), kSHA1Length);
}
} // namespace base
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