/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* The following code is based on the description in RFC 3174.
* http://www.ietf.org/rfc/rfc3174.txt
*/
#include "SkTypes.h"
#include "SkSHA1.h"
#include <string.h>
/** SHA1 basic transformation. Transforms state based on block. */
static void transform(uint32_t state[5], const uint8_t block[64]);
/** Encodes input into output (5 big endian 32 bit values). */
static void encode(uint8_t output[20], const uint32_t input[5]);
/** Encodes input into output (big endian 64 bit value). */
static void encode(uint8_t output[8], const uint64_t input);
SkSHA1::SkSHA1() : byteCount(0) {
// These are magic numbers from the specification. The first four are the same as MD5.
this->state[0] = 0x67452301;
this->state[1] = 0xefcdab89;
this->state[2] = 0x98badcfe;
this->state[3] = 0x10325476;
this->state[4] = 0xc3d2e1f0;
}
void SkSHA1::update(const uint8_t* input, size_t inputLength) {
unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
unsigned int bufferAvailable = 64 - bufferIndex;
unsigned int inputIndex;
if (inputLength >= bufferAvailable) {
if (bufferIndex) {
memcpy(&this->buffer[bufferIndex], input, bufferAvailable);
transform(this->state, this->buffer);
inputIndex = bufferAvailable;
} else {
inputIndex = 0;
}
for (; inputIndex + 63 < inputLength; inputIndex += 64) {
transform(this->state, &input[inputIndex]);
}
bufferIndex = 0;
} else {
inputIndex = 0;
}
memcpy(&this->buffer[bufferIndex], &input[inputIndex], inputLength - inputIndex);
this->byteCount += inputLength;
}
void SkSHA1::finish(Digest& digest) {
// Get the number of bits before padding.
uint8_t bits[8];
encode(bits, this->byteCount << 3);
// Pad out to 56 mod 64.
unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
unsigned int paddingLength = (bufferIndex < 56) ? (56 - bufferIndex) : (120 - bufferIndex);
static uint8_t PADDING[64] = {
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, 0, 0,
};
this->update(PADDING, paddingLength);
// Append length (length before padding, will cause final update).
this->update(bits, 8);
// Write out digest.
encode(digest.data, this->state);
#if defined(SK_SHA1_CLEAR_DATA)
// Clear state.
memset(this, 0, sizeof(*this));
#endif
}
struct F1 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
return (B & C) | ((~B) & D);
//return D ^ (B & (C ^ D));
//return (B & C) ^ ((~B) & D);
//return (B & C) + ((~B) & D);
//return _mm_or_ps(_mm_andnot_ps(B, D), _mm_and_ps(B, C)); //SSE2
//return vec_sel(D, C, B); //PPC
}};
struct F2 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
return B ^ C ^ D;
}};
struct F3 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
return (B & C) | (B & D) | (C & D);
//return (B & C) | (D & (B | C));
//return (B & C) | (D & (B ^ C));
//return (B & C) + (D & (B ^ C));
//return (B & C) ^ (B & D) ^ (C & D);
}};
/** Rotates x left n bits. */
static inline uint32_t rotate_left(uint32_t x, uint8_t n) {
return (x << n) | (x >> (32 - n));
}
template <typename T>
static inline void operation(T operation,
uint32_t A, uint32_t& B, uint32_t C, uint32_t D, uint32_t& E,
uint32_t w, uint32_t k) {
E += rotate_left(A, 5) + operation(B, C, D) + w + k;
B = rotate_left(B, 30);
}
static void transform(uint32_t state[5], const uint8_t block[64]) {
uint32_t A = state[0], B = state[1], C = state[2], D = state[3], E = state[4];
// Round constants defined in SHA-1.
static const uint32_t K[] = {
0x5A827999, //sqrt(2) * 2^30
0x6ED9EBA1, //sqrt(3) * 2^30
0x8F1BBCDC, //sqrt(5) * 2^30
0xCA62C1D6, //sqrt(10) * 2^30
};
uint32_t W[80];
// Initialize the array W.
size_t i = 0;
for (size_t j = 0; i < 16; ++i, j += 4) {
W[i] = (((uint32_t)block[j ]) << 24) |
(((uint32_t)block[j+1]) << 16) |
(((uint32_t)block[j+2]) << 8) |
(((uint32_t)block[j+3]) );
}
for (; i < 80; ++i) {
W[i] = rotate_left(W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16], 1);
//The following is equivelent and speeds up SSE implementations, but slows non-SSE.
//W[i] = rotate_left(W[i-6] ^ W[i-16] ^ W[i-28] ^ W[i-32], 2);
}
// Round 1
operation(F1(), A, B, C, D, E, W[ 0], K[0]);
operation(F1(), E, A, B, C, D, W[ 1], K[0]);
operation(F1(), D, E, A, B, C, W[ 2], K[0]);
operation(F1(), C, D, E, A, B, W[ 3], K[0]);
operation(F1(), B, C, D, E, A, W[ 4], K[0]);
operation(F1(), A, B, C, D, E, W[ 5], K[0]);
operation(F1(), E, A, B, C, D, W[ 6], K[0]);
operation(F1(), D, E, A, B, C, W[ 7], K[0]);
operation(F1(), C, D, E, A, B, W[ 8], K[0]);
operation(F1(), B, C, D, E, A, W[ 9], K[0]);
operation(F1(), A, B, C, D, E, W[10], K[0]);
operation(F1(), E, A, B, C, D, W[11], K[0]);
operation(F1(), D, E, A, B, C, W[12], K[0]);
operation(F1(), C, D, E, A, B, W[13], K[0]);
operation(F1(), B, C, D, E, A, W[14], K[0]);
operation(F1(), A, B, C, D, E, W[15], K[0]);
operation(F1(), E, A, B, C, D, W[16], K[0]);
operation(F1(), D, E, A, B, C, W[17], K[0]);
operation(F1(), C, D, E, A, B, W[18], K[0]);
operation(F1(), B, C, D, E, A, W[19], K[0]);
// Round 2
operation(F2(), A, B, C, D, E, W[20], K[1]);
operation(F2(), E, A, B, C, D, W[21], K[1]);
operation(F2(), D, E, A, B, C, W[22], K[1]);
operation(F2(), C, D, E, A, B, W[23], K[1]);
operation(F2(), B, C, D, E, A, W[24], K[1]);
operation(F2(), A, B, C, D, E, W[25], K[1]);
operation(F2(), E, A, B, C, D, W[26], K[1]);
operation(F2(), D, E, A, B, C, W[27], K[1]);
operation(F2(), C, D, E, A, B, W[28], K[1]);
operation(F2(), B, C, D, E, A, W[29], K[1]);
operation(F2(), A, B, C, D, E, W[30], K[1]);
operation(F2(), E, A, B, C, D, W[31], K[1]);
operation(F2(), D, E, A, B, C, W[32], K[1]);
operation(F2(), C, D, E, A, B, W[33], K[1]);
operation(F2(), B, C, D, E, A, W[34], K[1]);
operation(F2(), A, B, C, D, E, W[35], K[1]);
operation(F2(), E, A, B, C, D, W[36], K[1]);
operation(F2(), D, E, A, B, C, W[37], K[1]);
operation(F2(), C, D, E, A, B, W[38], K[1]);
operation(F2(), B, C, D, E, A, W[39], K[1]);
// Round 3
operation(F3(), A, B, C, D, E, W[40], K[2]);
operation(F3(), E, A, B, C, D, W[41], K[2]);
operation(F3(), D, E, A, B, C, W[42], K[2]);
operation(F3(), C, D, E, A, B, W[43], K[2]);
operation(F3(), B, C, D, E, A, W[44], K[2]);
operation(F3(), A, B, C, D, E, W[45], K[2]);
operation(F3(), E, A, B, C, D, W[46], K[2]);
operation(F3(), D, E, A, B, C, W[47], K[2]);
operation(F3(), C, D, E, A, B, W[48], K[2]);
operation(F3(), B, C, D, E, A, W[49], K[2]);
operation(F3(), A, B, C, D, E, W[50], K[2]);
operation(F3(), E, A, B, C, D, W[51], K[2]);
operation(F3(), D, E, A, B, C, W[52], K[2]);
operation(F3(), C, D, E, A, B, W[53], K[2]);
operation(F3(), B, C, D, E, A, W[54], K[2]);
operation(F3(), A, B, C, D, E, W[55], K[2]);
operation(F3(), E, A, B, C, D, W[56], K[2]);
operation(F3(), D, E, A, B, C, W[57], K[2]);
operation(F3(), C, D, E, A, B, W[58], K[2]);
operation(F3(), B, C, D, E, A, W[59], K[2]);
// Round 4
operation(F2(), A, B, C, D, E, W[60], K[3]);
operation(F2(), E, A, B, C, D, W[61], K[3]);
operation(F2(), D, E, A, B, C, W[62], K[3]);
operation(F2(), C, D, E, A, B, W[63], K[3]);
operation(F2(), B, C, D, E, A, W[64], K[3]);
operation(F2(), A, B, C, D, E, W[65], K[3]);
operation(F2(), E, A, B, C, D, W[66], K[3]);
operation(F2(), D, E, A, B, C, W[67], K[3]);
operation(F2(), C, D, E, A, B, W[68], K[3]);
operation(F2(), B, C, D, E, A, W[69], K[3]);
operation(F2(), A, B, C, D, E, W[70], K[3]);
operation(F2(), E, A, B, C, D, W[71], K[3]);
operation(F2(), D, E, A, B, C, W[72], K[3]);
operation(F2(), C, D, E, A, B, W[73], K[3]);
operation(F2(), B, C, D, E, A, W[74], K[3]);
operation(F2(), A, B, C, D, E, W[75], K[3]);
operation(F2(), E, A, B, C, D, W[76], K[3]);
operation(F2(), D, E, A, B, C, W[77], K[3]);
operation(F2(), C, D, E, A, B, W[78], K[3]);
operation(F2(), B, C, D, E, A, W[79], K[3]);
state[0] += A;
state[1] += B;
state[2] += C;
state[3] += D;
state[4] += E;
#if defined(SK_SHA1_CLEAR_DATA)
// Clear sensitive information.
memset(W, 0, sizeof(W));
#endif
}
static void encode(uint8_t output[20], const uint32_t input[5]) {
for (size_t i = 0, j = 0; i < 5; i++, j += 4) {
output[j ] = (uint8_t)((input[i] >> 24) & 0xff);
output[j+1] = (uint8_t)((input[i] >> 16) & 0xff);
output[j+2] = (uint8_t)((input[i] >> 8) & 0xff);
output[j+3] = (uint8_t)((input[i] ) & 0xff);
}
}
static void encode(uint8_t output[8], const uint64_t input) {
output[0] = (uint8_t)((input >> 56) & 0xff);
output[1] = (uint8_t)((input >> 48) & 0xff);
output[2] = (uint8_t)((input >> 40) & 0xff);
output[3] = (uint8_t)((input >> 32) & 0xff);
output[4] = (uint8_t)((input >> 24) & 0xff);
output[5] = (uint8_t)((input >> 16) & 0xff);
output[6] = (uint8_t)((input >> 8) & 0xff);
output[7] = (uint8_t)((input ) & 0xff);
}