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Diffstat (limited to 'src/crypto/chacha/chacha_generic.c')
| -rw-r--r-- | src/crypto/chacha/chacha_generic.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/src/crypto/chacha/chacha_generic.c b/src/crypto/chacha/chacha_generic.c new file mode 100644 index 0000000..31cf4f0 --- /dev/null +++ b/src/crypto/chacha/chacha_generic.c @@ -0,0 +1,143 @@ +/* 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__ */ |