/* 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" #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)) // 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)))) // 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); void CRYPTO_hchacha20(uint8_t out[32], const uint8_t key[32], const uint8_t nonce[16]) { uint32_t x[16]; OPENSSL_memcpy(x, sigma, sizeof(sigma)); OPENSSL_memcpy(&x[4], key, 32); OPENSSL_memcpy(&x[12], nonce, 16); for (size_t i = 0; i < 20; 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) } OPENSSL_memcpy(out, &x[0], sizeof(uint32_t) * 4); OPENSSL_memcpy(&out[16], &x[12], sizeof(uint32_t) * 4); } #if defined(CHACHA20_ASM) 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 #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; \ } // 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; OPENSSL_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