michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  *
michael@0:  * The following code is based on the description in RFC 3174.
michael@0:  * http://www.ietf.org/rfc/rfc3174.txt
michael@0:  */
michael@0: 
michael@0: #include "SkTypes.h"
michael@0: #include "SkSHA1.h"
michael@0: #include <string.h>
michael@0: 
michael@0: /** SHA1 basic transformation. Transforms state based on block. */
michael@0: static void transform(uint32_t state[5], const uint8_t block[64]);
michael@0: 
michael@0: /** Encodes input into output (5 big endian 32 bit values). */
michael@0: static void encode(uint8_t output[20], const uint32_t input[5]);
michael@0: 
michael@0: /** Encodes input into output (big endian 64 bit value). */
michael@0: static void encode(uint8_t output[8], const uint64_t input);
michael@0: 
michael@0: SkSHA1::SkSHA1() : byteCount(0) {
michael@0:     // These are magic numbers from the specification. The first four are the same as MD5.
michael@0:     this->state[0] = 0x67452301;
michael@0:     this->state[1] = 0xefcdab89;
michael@0:     this->state[2] = 0x98badcfe;
michael@0:     this->state[3] = 0x10325476;
michael@0:     this->state[4] = 0xc3d2e1f0;
michael@0: }
michael@0: 
michael@0: void SkSHA1::update(const uint8_t* input, size_t inputLength) {
michael@0:     unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
michael@0:     unsigned int bufferAvailable = 64 - bufferIndex;
michael@0: 
michael@0:     unsigned int inputIndex;
michael@0:     if (inputLength >= bufferAvailable) {
michael@0:         if (bufferIndex) {
michael@0:             memcpy(&this->buffer[bufferIndex], input, bufferAvailable);
michael@0:             transform(this->state, this->buffer);
michael@0:             inputIndex = bufferAvailable;
michael@0:         } else {
michael@0:             inputIndex = 0;
michael@0:         }
michael@0: 
michael@0:         for (; inputIndex + 63 < inputLength; inputIndex += 64) {
michael@0:             transform(this->state, &input[inputIndex]);
michael@0:         }
michael@0: 
michael@0:         bufferIndex = 0;
michael@0:     } else {
michael@0:         inputIndex = 0;
michael@0:     }
michael@0: 
michael@0:     memcpy(&this->buffer[bufferIndex], &input[inputIndex], inputLength - inputIndex);
michael@0: 
michael@0:     this->byteCount += inputLength;
michael@0: }
michael@0: 
michael@0: void SkSHA1::finish(Digest& digest) {
michael@0:     // Get the number of bits before padding.
michael@0:     uint8_t bits[8];
michael@0:     encode(bits, this->byteCount << 3);
michael@0: 
michael@0:     // Pad out to 56 mod 64.
michael@0:     unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
michael@0:     unsigned int paddingLength = (bufferIndex < 56) ? (56 - bufferIndex) : (120 - bufferIndex);
michael@0:     static uint8_t PADDING[64] = {
michael@0:         0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
michael@0:            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
michael@0:            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
michael@0:            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
michael@0:     };
michael@0:     this->update(PADDING, paddingLength);
michael@0: 
michael@0:     // Append length (length before padding, will cause final update).
michael@0:     this->update(bits, 8);
michael@0: 
michael@0:     // Write out digest.
michael@0:     encode(digest.data, this->state);
michael@0: 
michael@0: #if defined(SK_SHA1_CLEAR_DATA)
michael@0:     // Clear state.
michael@0:     memset(this, 0, sizeof(*this));
michael@0: #endif
michael@0: }
michael@0: 
michael@0: struct F1 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
michael@0:     return (B & C) | ((~B) & D);
michael@0:     //return D ^ (B & (C ^ D));
michael@0:     //return (B & C) ^ ((~B) & D);
michael@0:     //return (B & C) + ((~B) & D);
michael@0:     //return _mm_or_ps(_mm_andnot_ps(B, D), _mm_and_ps(B, C)); //SSE2
michael@0:     //return vec_sel(D, C, B); //PPC
michael@0: }};
michael@0: 
michael@0: struct F2 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
michael@0:     return B ^ C ^ D;
michael@0: }};
michael@0: 
michael@0: struct F3 { uint32_t operator()(uint32_t B, uint32_t C, uint32_t D) {
michael@0:     return (B & C) | (B & D) | (C & D);
michael@0:     //return (B & C) | (D & (B | C));
michael@0:     //return (B & C) | (D & (B ^ C));
michael@0:     //return (B & C) + (D & (B ^ C));
michael@0:     //return (B & C) ^ (B & D) ^ (C & D);
michael@0: }};
michael@0: 
michael@0: /** Rotates x left n bits. */
michael@0: static inline uint32_t rotate_left(uint32_t x, uint8_t n) {
michael@0:     return (x << n) | (x >> (32 - n));
michael@0: }
michael@0: 
michael@0: template <typename T>
michael@0: static inline void operation(T operation,
michael@0:                              uint32_t A, uint32_t& B, uint32_t C, uint32_t D, uint32_t& E,
michael@0:                              uint32_t w, uint32_t k) {
michael@0:     E += rotate_left(A, 5) + operation(B, C, D) + w + k;
michael@0:     B = rotate_left(B, 30);
michael@0: }
michael@0: 
michael@0: static void transform(uint32_t state[5], const uint8_t block[64]) {
michael@0:     uint32_t A = state[0], B = state[1], C = state[2], D = state[3], E = state[4];
michael@0: 
michael@0:     // Round constants defined in SHA-1.
michael@0:     static const uint32_t K[] = {
michael@0:         0x5A827999, //sqrt(2) * 2^30
michael@0:         0x6ED9EBA1, //sqrt(3) * 2^30
michael@0:         0x8F1BBCDC, //sqrt(5) * 2^30
michael@0:         0xCA62C1D6, //sqrt(10) * 2^30
michael@0:     };
michael@0: 
michael@0:     uint32_t W[80];
michael@0: 
michael@0:     // Initialize the array W.
michael@0:     size_t i = 0;
michael@0:     for (size_t j = 0; i < 16; ++i, j += 4) {
michael@0:         W[i] = (((uint32_t)block[j  ]) << 24) |
michael@0:                (((uint32_t)block[j+1]) << 16) |
michael@0:                (((uint32_t)block[j+2]) <<  8) |
michael@0:                (((uint32_t)block[j+3])      );
michael@0:     }
michael@0:     for (; i < 80; ++i) {
michael@0:        W[i] = rotate_left(W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16], 1);
michael@0:        //The following is equivelent and speeds up SSE implementations, but slows non-SSE.
michael@0:        //W[i] = rotate_left(W[i-6] ^ W[i-16] ^ W[i-28] ^ W[i-32], 2);
michael@0:     }
michael@0: 
michael@0:     // Round 1
michael@0:     operation(F1(), A, B, C, D, E, W[ 0], K[0]);
michael@0:     operation(F1(), E, A, B, C, D, W[ 1], K[0]);
michael@0:     operation(F1(), D, E, A, B, C, W[ 2], K[0]);
michael@0:     operation(F1(), C, D, E, A, B, W[ 3], K[0]);
michael@0:     operation(F1(), B, C, D, E, A, W[ 4], K[0]);
michael@0:     operation(F1(), A, B, C, D, E, W[ 5], K[0]);
michael@0:     operation(F1(), E, A, B, C, D, W[ 6], K[0]);
michael@0:     operation(F1(), D, E, A, B, C, W[ 7], K[0]);
michael@0:     operation(F1(), C, D, E, A, B, W[ 8], K[0]);
michael@0:     operation(F1(), B, C, D, E, A, W[ 9], K[0]);
michael@0:     operation(F1(), A, B, C, D, E, W[10], K[0]);
michael@0:     operation(F1(), E, A, B, C, D, W[11], K[0]);
michael@0:     operation(F1(), D, E, A, B, C, W[12], K[0]);
michael@0:     operation(F1(), C, D, E, A, B, W[13], K[0]);
michael@0:     operation(F1(), B, C, D, E, A, W[14], K[0]);
michael@0:     operation(F1(), A, B, C, D, E, W[15], K[0]);
michael@0:     operation(F1(), E, A, B, C, D, W[16], K[0]);
michael@0:     operation(F1(), D, E, A, B, C, W[17], K[0]);
michael@0:     operation(F1(), C, D, E, A, B, W[18], K[0]);
michael@0:     operation(F1(), B, C, D, E, A, W[19], K[0]);
michael@0: 
michael@0:     // Round 2
michael@0:     operation(F2(), A, B, C, D, E, W[20], K[1]);
michael@0:     operation(F2(), E, A, B, C, D, W[21], K[1]);
michael@0:     operation(F2(), D, E, A, B, C, W[22], K[1]);
michael@0:     operation(F2(), C, D, E, A, B, W[23], K[1]);
michael@0:     operation(F2(), B, C, D, E, A, W[24], K[1]);
michael@0:     operation(F2(), A, B, C, D, E, W[25], K[1]);
michael@0:     operation(F2(), E, A, B, C, D, W[26], K[1]);
michael@0:     operation(F2(), D, E, A, B, C, W[27], K[1]);
michael@0:     operation(F2(), C, D, E, A, B, W[28], K[1]);
michael@0:     operation(F2(), B, C, D, E, A, W[29], K[1]);
michael@0:     operation(F2(), A, B, C, D, E, W[30], K[1]);
michael@0:     operation(F2(), E, A, B, C, D, W[31], K[1]);
michael@0:     operation(F2(), D, E, A, B, C, W[32], K[1]);
michael@0:     operation(F2(), C, D, E, A, B, W[33], K[1]);
michael@0:     operation(F2(), B, C, D, E, A, W[34], K[1]);
michael@0:     operation(F2(), A, B, C, D, E, W[35], K[1]);
michael@0:     operation(F2(), E, A, B, C, D, W[36], K[1]);
michael@0:     operation(F2(), D, E, A, B, C, W[37], K[1]);
michael@0:     operation(F2(), C, D, E, A, B, W[38], K[1]);
michael@0:     operation(F2(), B, C, D, E, A, W[39], K[1]);
michael@0: 
michael@0:     // Round 3
michael@0:     operation(F3(), A, B, C, D, E, W[40], K[2]);
michael@0:     operation(F3(), E, A, B, C, D, W[41], K[2]);
michael@0:     operation(F3(), D, E, A, B, C, W[42], K[2]);
michael@0:     operation(F3(), C, D, E, A, B, W[43], K[2]);
michael@0:     operation(F3(), B, C, D, E, A, W[44], K[2]);
michael@0:     operation(F3(), A, B, C, D, E, W[45], K[2]);
michael@0:     operation(F3(), E, A, B, C, D, W[46], K[2]);
michael@0:     operation(F3(), D, E, A, B, C, W[47], K[2]);
michael@0:     operation(F3(), C, D, E, A, B, W[48], K[2]);
michael@0:     operation(F3(), B, C, D, E, A, W[49], K[2]);
michael@0:     operation(F3(), A, B, C, D, E, W[50], K[2]);
michael@0:     operation(F3(), E, A, B, C, D, W[51], K[2]);
michael@0:     operation(F3(), D, E, A, B, C, W[52], K[2]);
michael@0:     operation(F3(), C, D, E, A, B, W[53], K[2]);
michael@0:     operation(F3(), B, C, D, E, A, W[54], K[2]);
michael@0:     operation(F3(), A, B, C, D, E, W[55], K[2]);
michael@0:     operation(F3(), E, A, B, C, D, W[56], K[2]);
michael@0:     operation(F3(), D, E, A, B, C, W[57], K[2]);
michael@0:     operation(F3(), C, D, E, A, B, W[58], K[2]);
michael@0:     operation(F3(), B, C, D, E, A, W[59], K[2]);
michael@0: 
michael@0:     // Round 4
michael@0:     operation(F2(), A, B, C, D, E, W[60], K[3]);
michael@0:     operation(F2(), E, A, B, C, D, W[61], K[3]);
michael@0:     operation(F2(), D, E, A, B, C, W[62], K[3]);
michael@0:     operation(F2(), C, D, E, A, B, W[63], K[3]);
michael@0:     operation(F2(), B, C, D, E, A, W[64], K[3]);
michael@0:     operation(F2(), A, B, C, D, E, W[65], K[3]);
michael@0:     operation(F2(), E, A, B, C, D, W[66], K[3]);
michael@0:     operation(F2(), D, E, A, B, C, W[67], K[3]);
michael@0:     operation(F2(), C, D, E, A, B, W[68], K[3]);
michael@0:     operation(F2(), B, C, D, E, A, W[69], K[3]);
michael@0:     operation(F2(), A, B, C, D, E, W[70], K[3]);
michael@0:     operation(F2(), E, A, B, C, D, W[71], K[3]);
michael@0:     operation(F2(), D, E, A, B, C, W[72], K[3]);
michael@0:     operation(F2(), C, D, E, A, B, W[73], K[3]);
michael@0:     operation(F2(), B, C, D, E, A, W[74], K[3]);
michael@0:     operation(F2(), A, B, C, D, E, W[75], K[3]);
michael@0:     operation(F2(), E, A, B, C, D, W[76], K[3]);
michael@0:     operation(F2(), D, E, A, B, C, W[77], K[3]);
michael@0:     operation(F2(), C, D, E, A, B, W[78], K[3]);
michael@0:     operation(F2(), B, C, D, E, A, W[79], K[3]);
michael@0: 
michael@0:     state[0] += A;
michael@0:     state[1] += B;
michael@0:     state[2] += C;
michael@0:     state[3] += D;
michael@0:     state[4] += E;
michael@0: 
michael@0: #if defined(SK_SHA1_CLEAR_DATA)
michael@0:     // Clear sensitive information.
michael@0:     memset(W, 0, sizeof(W));
michael@0: #endif
michael@0: }
michael@0: 
michael@0: static void encode(uint8_t output[20], const uint32_t input[5]) {
michael@0:     for (size_t i = 0, j = 0; i < 5; i++, j += 4) {
michael@0:         output[j  ] = (uint8_t)((input[i] >> 24) & 0xff);
michael@0:         output[j+1] = (uint8_t)((input[i] >> 16) & 0xff);
michael@0:         output[j+2] = (uint8_t)((input[i] >>  8) & 0xff);
michael@0:         output[j+3] = (uint8_t)((input[i]      ) & 0xff);
michael@0:     }
michael@0: }
michael@0: 
michael@0: static void encode(uint8_t output[8], const uint64_t input) {
michael@0:     output[0] = (uint8_t)((input >> 56) & 0xff);
michael@0:     output[1] = (uint8_t)((input >> 48) & 0xff);
michael@0:     output[2] = (uint8_t)((input >> 40) & 0xff);
michael@0:     output[3] = (uint8_t)((input >> 32) & 0xff);
michael@0:     output[4] = (uint8_t)((input >> 24) & 0xff);
michael@0:     output[5] = (uint8_t)((input >> 16) & 0xff);
michael@0:     output[6] = (uint8_t)((input >>  8) & 0xff);
michael@0:     output[7] = (uint8_t)((input      ) & 0xff);
michael@0: }