1 /* Copyright (c) 2014, Google Inc. 2 * 3 * Permission to use, copy, modify, and/or distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 14 15 /* Adapted from the public domain, estream code by D. Bernstein. */ 16 17 #include <openssl/chacha.h> 18 19 #include <string.h> 20 21 #include <openssl/cpu.h> 22 23 24 #if defined(OPENSSL_WINDOWS) || (!defined(OPENSSL_X86_64) && !defined(OPENSSL_X86)) || !defined(__SSE2__) 25 26 /* sigma contains the ChaCha constants, which happen to be an ASCII string. */ 27 static const uint8_t sigma[16] = { 'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', 28 '2', '-', 'b', 'y', 't', 'e', ' ', 'k' }; 29 30 #define ROTATE(v, n) (((v) << (n)) | ((v) >> (32 - (n)))) 31 #define XOR(v, w) ((v) ^ (w)) 32 #define PLUS(x, y) ((x) + (y)) 33 #define PLUSONE(v) (PLUS((v), 1)) 34 35 #define U32TO8_LITTLE(p, v) \ 36 { \ 37 (p)[0] = (v >> 0) & 0xff; \ 38 (p)[1] = (v >> 8) & 0xff; \ 39 (p)[2] = (v >> 16) & 0xff; \ 40 (p)[3] = (v >> 24) & 0xff; \ 41 } 42 43 #define U8TO32_LITTLE(p) \ 44 (((uint32_t)((p)[0])) | ((uint32_t)((p)[1]) << 8) | \ 45 ((uint32_t)((p)[2]) << 16) | ((uint32_t)((p)[3]) << 24)) 46 47 /* QUARTERROUND updates a, b, c, d with a ChaCha "quarter" round. */ 48 #define QUARTERROUND(a,b,c,d) \ 49 x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]),16); \ 50 x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]),12); \ 51 x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]), 8); \ 52 x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]), 7); 53 54 #if defined(OPENSSL_ARM) && !defined(OPENSSL_NO_ASM) 55 /* Defined in chacha_vec.c */ 56 void CRYPTO_chacha_20_neon(uint8_t *out, const uint8_t *in, size_t in_len, 57 const uint8_t key[32], const uint8_t nonce[8], 58 size_t counter); 59 #endif 60 61 /* chacha_core performs 20 rounds of ChaCha on the input words in 62 * |input| and writes the 64 output bytes to |output|. */ 63 static void chacha_core(uint8_t output[64], const uint32_t input[16]) { 64 uint32_t x[16]; 65 int i; 66 67 memcpy(x, input, sizeof(uint32_t) * 16); 68 for (i = 20; i > 0; i -= 2) { 69 QUARTERROUND(0, 4, 8, 12) 70 QUARTERROUND(1, 5, 9, 13) 71 QUARTERROUND(2, 6, 10, 14) 72 QUARTERROUND(3, 7, 11, 15) 73 QUARTERROUND(0, 5, 10, 15) 74 QUARTERROUND(1, 6, 11, 12) 75 QUARTERROUND(2, 7, 8, 13) 76 QUARTERROUND(3, 4, 9, 14) 77 } 78 79 for (i = 0; i < 16; ++i) { 80 x[i] = PLUS(x[i], input[i]); 81 } 82 for (i = 0; i < 16; ++i) { 83 U32TO8_LITTLE(output + 4 * i, x[i]); 84 } 85 } 86 87 void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in, size_t in_len, 88 const uint8_t key[32], const uint8_t nonce[8], 89 size_t counter) { 90 uint32_t input[16]; 91 uint8_t buf[64]; 92 size_t todo, i; 93 94 #if defined(OPENSSL_ARM) && !defined(OPENSSL_NO_ASM) 95 if (CRYPTO_is_NEON_capable()) { 96 CRYPTO_chacha_20_neon(out, in, in_len, key, nonce, counter); 97 return; 98 } 99 #endif 100 101 input[0] = U8TO32_LITTLE(sigma + 0); 102 input[1] = U8TO32_LITTLE(sigma + 4); 103 input[2] = U8TO32_LITTLE(sigma + 8); 104 input[3] = U8TO32_LITTLE(sigma + 12); 105 106 input[4] = U8TO32_LITTLE(key + 0); 107 input[5] = U8TO32_LITTLE(key + 4); 108 input[6] = U8TO32_LITTLE(key + 8); 109 input[7] = U8TO32_LITTLE(key + 12); 110 111 input[8] = U8TO32_LITTLE(key + 16); 112 input[9] = U8TO32_LITTLE(key + 20); 113 input[10] = U8TO32_LITTLE(key + 24); 114 input[11] = U8TO32_LITTLE(key + 28); 115 116 input[12] = counter; 117 input[13] = ((uint64_t)counter) >> 32; 118 input[14] = U8TO32_LITTLE(nonce + 0); 119 input[15] = U8TO32_LITTLE(nonce + 4); 120 121 while (in_len > 0) { 122 todo = sizeof(buf); 123 if (in_len < todo) { 124 todo = in_len; 125 } 126 127 chacha_core(buf, input); 128 for (i = 0; i < todo; i++) { 129 out[i] = in[i] ^ buf[i]; 130 } 131 132 out += todo; 133 in += todo; 134 in_len -= todo; 135 136 input[12]++; 137 if (input[12] == 0) { 138 input[13]++; 139 } 140 } 141 } 142 143 #endif /* OPENSSL_WINDOWS || !OPENSSL_X86_64 && !OPENSSL_X86 || !__SSE2__ */ 144
