- /* 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 <string.h>
-
- #include <openssl/cpu.h>
-
-
- #if defined(OPENSSL_WINDOWS) || (!defined(OPENSSL_X86_64) && !defined(OPENSSL_X86)) || !defined(__SSE2__)
-
- /* 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 XOR(v, w) ((v) ^ (w))
- #define PLUS(x, y) ((x) + (y))
- #define PLUSONE(v) (PLUS((v), 1))
-
- #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; \
- }
-
- #define U8TO32_LITTLE(p) \
- (((uint32_t)((p)[0])) | ((uint32_t)((p)[1]) << 8) | \
- ((uint32_t)((p)[2]) << 16) | ((uint32_t)((p)[3]) << 24))
-
- /* QUARTERROUND updates a, b, c, d with a ChaCha "quarter" round. */
- #define QUARTERROUND(a,b,c,d) \
- x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]),16); \
- x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]),12); \
- x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]), 8); \
- x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]), 7);
-
- #if defined(OPENSSL_ARM) && !defined(OPENSSL_NO_ASM)
- /* Defined in chacha_vec.c */
- void CRYPTO_chacha_20_neon(uint8_t *out, const uint8_t *in, size_t in_len,
- const uint8_t key[32], const uint8_t nonce[8],
- size_t counter);
- #endif
-
- /* 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] = PLUS(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[8],
- size_t counter) {
- uint32_t input[16];
- uint8_t buf[64];
- size_t todo, i;
-
- #if defined(OPENSSL_ARM) && !defined(OPENSSL_NO_ASM)
- if (CRYPTO_is_NEON_capable()) {
- CRYPTO_chacha_20_neon(out, in, in_len, key, nonce, counter);
- return;
- }
- #endif
-
- 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] = ((uint64_t)counter) >> 32;
- input[14] = U8TO32_LITTLE(nonce + 0);
- input[15] = U8TO32_LITTLE(nonce + 4);
-
- 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]++;
- if (input[12] == 0) {
- input[13]++;
- }
- }
- }
-
- #endif /* OPENSSL_WINDOWS || !OPENSSL_X86_64 && !OPENSSL_X86 || !__SSE2__ */
|