| /* Copyright (c) 2014, Google Inc. |
| * |
| * Permission to use, copy, modify, and/or distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
| * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ |
| |
| /* Adapted from the public domain, estream code by D. Bernstein. */ |
| |
| #include <openssl/chacha.h> |
| |
| #include <assert.h> |
| #include <string.h> |
| |
| #include <openssl/cpu.h> |
| |
| #include "../internal.h" |
| |
| |
| #define U8TO32_LITTLE(p) \ |
| (((uint32_t)((p)[0])) | ((uint32_t)((p)[1]) << 8) | \ |
| ((uint32_t)((p)[2]) << 16) | ((uint32_t)((p)[3]) << 24)) |
| |
| #if !defined(OPENSSL_NO_ASM) && \ |
| (defined(OPENSSL_X86) || defined(OPENSSL_X86_64) || \ |
| defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64)) |
| |
| /* ChaCha20_ctr32 is defined in asm/chacha-*.pl. */ |
| void ChaCha20_ctr32(uint8_t *out, const uint8_t *in, size_t in_len, |
| const uint32_t key[8], const uint32_t counter[4]); |
| |
| void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in, size_t in_len, |
| const uint8_t key[32], const uint8_t nonce[12], |
| uint32_t counter) { |
| assert(!buffers_alias(out, in_len, in, in_len) || in == out); |
| |
| uint32_t counter_nonce[4]; counter_nonce[0] = counter; |
| counter_nonce[1] = U8TO32_LITTLE(nonce + 0); |
| counter_nonce[2] = U8TO32_LITTLE(nonce + 4); |
| counter_nonce[3] = U8TO32_LITTLE(nonce + 8); |
| |
| const uint32_t *key_ptr = (const uint32_t *)key; |
| #if !defined(OPENSSL_X86) && !defined(OPENSSL_X86_64) |
| /* The assembly expects the key to be four-byte aligned. */ |
| uint32_t key_u32[8]; |
| if ((((uintptr_t)key) & 3) != 0) { |
| key_u32[0] = U8TO32_LITTLE(key + 0); |
| key_u32[1] = U8TO32_LITTLE(key + 4); |
| key_u32[2] = U8TO32_LITTLE(key + 8); |
| key_u32[3] = U8TO32_LITTLE(key + 12); |
| key_u32[4] = U8TO32_LITTLE(key + 16); |
| key_u32[5] = U8TO32_LITTLE(key + 20); |
| key_u32[6] = U8TO32_LITTLE(key + 24); |
| key_u32[7] = U8TO32_LITTLE(key + 28); |
| |
| key_ptr = key_u32; |
| } |
| #endif |
| |
| ChaCha20_ctr32(out, in, in_len, key_ptr, counter_nonce); |
| } |
| |
| #else |
| |
| /* sigma contains the ChaCha constants, which happen to be an ASCII string. */ |
| static const uint8_t sigma[16] = { 'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', |
| '2', '-', 'b', 'y', 't', 'e', ' ', 'k' }; |
| |
| #define ROTATE(v, n) (((v) << (n)) | ((v) >> (32 - (n)))) |
| |
| #define U32TO8_LITTLE(p, v) \ |
| { \ |
| (p)[0] = (v >> 0) & 0xff; \ |
| (p)[1] = (v >> 8) & 0xff; \ |
| (p)[2] = (v >> 16) & 0xff; \ |
| (p)[3] = (v >> 24) & 0xff; \ |
| } |
| |
| /* QUARTERROUND updates a, b, c, d with a ChaCha "quarter" round. */ |
| #define QUARTERROUND(a, b, c, d) \ |
| x[a] += x[b]; x[d] = ROTATE(x[d] ^ x[a], 16); \ |
| x[c] += x[d]; x[b] = ROTATE(x[b] ^ x[c], 12); \ |
| x[a] += x[b]; x[d] = ROTATE(x[d] ^ x[a], 8); \ |
| x[c] += x[d]; x[b] = ROTATE(x[b] ^ x[c], 7); |
| |
| /* chacha_core performs 20 rounds of ChaCha on the input words in |
| * |input| and writes the 64 output bytes to |output|. */ |
| static void chacha_core(uint8_t output[64], const uint32_t input[16]) { |
| uint32_t x[16]; |
| int i; |
| |
| memcpy(x, input, sizeof(uint32_t) * 16); |
| for (i = 20; i > 0; i -= 2) { |
| QUARTERROUND(0, 4, 8, 12) |
| QUARTERROUND(1, 5, 9, 13) |
| QUARTERROUND(2, 6, 10, 14) |
| QUARTERROUND(3, 7, 11, 15) |
| QUARTERROUND(0, 5, 10, 15) |
| QUARTERROUND(1, 6, 11, 12) |
| QUARTERROUND(2, 7, 8, 13) |
| QUARTERROUND(3, 4, 9, 14) |
| } |
| |
| for (i = 0; i < 16; ++i) { |
| x[i] += input[i]; |
| } |
| for (i = 0; i < 16; ++i) { |
| U32TO8_LITTLE(output + 4 * i, x[i]); |
| } |
| } |
| |
| void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in, size_t in_len, |
| const uint8_t key[32], const uint8_t nonce[12], |
| uint32_t counter) { |
| assert(!buffers_alias(out, in_len, in, in_len) || in == out); |
| |
| uint32_t input[16]; |
| uint8_t buf[64]; |
| size_t todo, i; |
| |
| input[0] = U8TO32_LITTLE(sigma + 0); |
| input[1] = U8TO32_LITTLE(sigma + 4); |
| input[2] = U8TO32_LITTLE(sigma + 8); |
| input[3] = U8TO32_LITTLE(sigma + 12); |
| |
| input[4] = U8TO32_LITTLE(key + 0); |
| input[5] = U8TO32_LITTLE(key + 4); |
| input[6] = U8TO32_LITTLE(key + 8); |
| input[7] = U8TO32_LITTLE(key + 12); |
| |
| input[8] = U8TO32_LITTLE(key + 16); |
| input[9] = U8TO32_LITTLE(key + 20); |
| input[10] = U8TO32_LITTLE(key + 24); |
| input[11] = U8TO32_LITTLE(key + 28); |
| |
| input[12] = counter; |
| input[13] = U8TO32_LITTLE(nonce + 0); |
| input[14] = U8TO32_LITTLE(nonce + 4); |
| input[15] = U8TO32_LITTLE(nonce + 8); |
| |
| while (in_len > 0) { |
| todo = sizeof(buf); |
| if (in_len < todo) { |
| todo = in_len; |
| } |
| |
| chacha_core(buf, input); |
| for (i = 0; i < todo; i++) { |
| out[i] = in[i] ^ buf[i]; |
| } |
| |
| out += todo; |
| in += todo; |
| in_len -= todo; |
| |
| input[12]++; |
| } |
| } |
| |
| #endif |