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// A straightforward SHA-1 implementation based on RFC 3174.
// http://www.ietf.org/rfc/rfc3174.txt
// The names of functions and variables (such as "a", "b", and "f") follow notations in RFC 3174.
#include "config.h"
#include "SHA1.h"
#include "Assertions.h"
#ifndef NDEBUG
#include "StringExtras.h"
#include "text/CString.h"
#endif
namespace WTF {
#ifdef NDEBUG
static inline void testSHA1() { }
#else
static bool isTestSHA1Done;
static void expectSHA1(CString input, int repeat, CString expected)
{
SHA1 sha1;
for (int i = 0; i < repeat; ++i)
sha1.addBytes(reinterpret_cast<const uint8_t*>(input.data()), input.length());
Vector<uint8_t, 20> digest;
sha1.computeHash(digest);
char* buffer = 0;
CString actual = CString::newUninitialized(40, buffer);
for (size_t i = 0; i < 20; ++i) {
snprintf(buffer, 3, "%02X", digest.at(i));
buffer += 2;
}
ASSERT_WITH_MESSAGE(actual == expected, "input: %s, repeat: %d, actual: %s, expected: %s", input.data(), repeat, actual.data(), expected.data());
}
static void testSHA1()
{
if (isTestSHA1Done)
return;
isTestSHA1Done = true;
// Examples taken from sample code in RFC 3174.
expectSHA1("abc", 1, "A9993E364706816ABA3E25717850C26C9CD0D89D");
expectSHA1("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", 1, "84983E441C3BD26EBAAE4AA1F95129E5E54670F1");
expectSHA1("a", 1000000, "34AA973CD4C4DAA4F61EEB2BDBAD27316534016F");
expectSHA1("0123456701234567012345670123456701234567012345670123456701234567", 10, "DEA356A2CDDD90C7A7ECEDC5EBB563934F460452");
}
#endif
static inline uint32_t f(int t, uint32_t b, uint32_t c, uint32_t d)
{
ASSERT(t >= 0 && t < 80);
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 k(int t)
{
ASSERT(t >= 0 && t < 80);
if (t < 20)
return 0x5a827999;
if (t < 40)
return 0x6ed9eba1;
if (t < 60)
return 0x8f1bbcdc;
return 0xca62c1d6;
}
static inline uint32_t rotateLeft(int n, uint32_t x)
{
ASSERT(n >= 0 && n < 32);
return (x << n) | (x >> (32 - n));
}
SHA1::SHA1()
{
// FIXME: Move unit tests somewhere outside the constructor. See bug 55853.
testSHA1();
reset();
}
void SHA1::addBytes(const uint8_t* input, size_t length)
{
while (length--) {
ASSERT(m_cursor < 64);
m_buffer[m_cursor++] = *input++;
++m_totalBytes;
if (m_cursor == 64)
processBlock();
}
}
void SHA1::computeHash(Vector<uint8_t, 20>& digest)
{
finalize();
digest.clear();
digest.resize(20);
for (size_t i = 0; i < 5; ++i) {
// Treat hashValue as a big-endian value.
uint32_t hashValue = m_hash[i];
for (int j = 0; j < 4; ++j) {
digest[4 * i + (3 - j)] = hashValue & 0xFF;
hashValue >>= 8;
}
}
reset();
}
void SHA1::finalize()
{
ASSERT(m_cursor < 64);
m_buffer[m_cursor++] = 0x80;
if (m_cursor > 56) {
// Pad out to next block.
while (m_cursor < 64)
m_buffer[m_cursor++] = 0x00;
processBlock();
}
for (size_t i = m_cursor; i < 56; ++i)
m_buffer[i] = 0x00;
// Write the length as a big-endian 64-bit value.
uint64_t bits = m_totalBytes * 8;
for (int i = 0; i < 8; ++i) {
m_buffer[56 + (7 - i)] = bits & 0xFF;
bits >>= 8;
}
m_cursor = 64;
processBlock();
}
void SHA1::processBlock()
{
ASSERT(m_cursor == 64);
uint32_t w[80] = { 0 };
for (int t = 0; t < 16; ++t)
w[t] = (m_buffer[t * 4] << 24) | (m_buffer[t * 4 + 1] << 16) | (m_buffer[t * 4 + 2] << 8) | m_buffer[t * 4 + 3];
for (int t = 16; t < 80; ++t)
w[t] = rotateLeft(1, w[t - 3] ^ w[t - 8] ^ w[t - 14] ^ w[t - 16]);
uint32_t a = m_hash[0];
uint32_t b = m_hash[1];
uint32_t c = m_hash[2];
uint32_t d = m_hash[3];
uint32_t e = m_hash[4];
for (int t = 0; t < 80; ++t) {
uint32_t temp = rotateLeft(5, a) + f(t, b, c, d) + e + w[t] + k(t);
e = d;
d = c;
c = rotateLeft(30, b);
b = a;
a = temp;
}
m_hash[0] += a;
m_hash[1] += b;
m_hash[2] += c;
m_hash[3] += d;
m_hash[4] += e;
m_cursor = 0;
}
void SHA1::reset()
{
m_cursor = 0;
m_totalBytes = 0;
m_hash[0] = 0x67452301;
m_hash[1] = 0xefcdab89;
m_hash[2] = 0x98badcfe;
m_hash[3] = 0x10325476;
m_hash[4] = 0xc3d2e1f0;
// Clear the buffer after use in case it's sensitive.
memset(m_buffer, 0, sizeof(m_buffer));
}
} // namespace WTF