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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| 4 |
| 5 /* Adopted from the public domain code in NaCl by djb. */ |
| 6 |
| 7 #include <string.h> |
| 8 #include <stdio.h> |
| 9 |
| 10 #include "prtypes.h" |
| 11 #include "secport.h" |
| 12 #include "chacha20.h" |
| 13 |
| 14 #if defined(_MSC_VER) |
| 15 #pragma intrinsic(_lrotl) |
| 16 #define ROTL32(x, n) _lrotl(x, n) |
| 17 #else |
| 18 #define ROTL32(x, n) ((x << n) | (x >> ((8 * sizeof x) - n))) |
| 19 #endif |
| 20 |
| 21 #define ROTATE(v, c) ROTL32((v), (c)) |
| 22 |
| 23 #define U32TO8_LITTLE(p, v) \ |
| 24 { (p)[0] = ((v) ) & 0xff; (p)[1] = ((v) >> 8) & 0xff; \ |
| 25 (p)[2] = ((v) >> 16) & 0xff; (p)[3] = ((v) >> 24) & 0xff; } |
| 26 #define U8TO32_LITTLE(p) \ |
| 27 (((PRUint32)((p)[0]) ) | ((PRUint32)((p)[1]) << 8) | \ |
| 28 ((PRUint32)((p)[2]) << 16) | ((PRUint32)((p)[3]) << 24)) |
| 29 |
| 30 #define QUARTERROUND(x, a, b, c, d) \ |
| 31 x[a] = x[a] + x[b]; x[d] = ROTATE(x[d] ^ x[a], 16); \ |
| 32 x[c] = x[c] + x[d]; x[b] = ROTATE(x[b] ^ x[c], 12); \ |
| 33 x[a] = x[a] + x[b]; x[d] = ROTATE(x[d] ^ x[a], 8); \ |
| 34 x[c] = x[c] + x[d]; x[b] = ROTATE(x[b] ^ x[c], 7); |
| 35 |
| 36 static void |
| 37 ChaChaCore(unsigned char output[64], const PRUint32 input[16], int num_rounds) |
| 38 { |
| 39 PRUint32 x[16]; |
| 40 int i; |
| 41 |
| 42 PORT_Memcpy(x, input, sizeof(PRUint32) * 16); |
| 43 for (i = num_rounds; i > 0; i -= 2) { |
| 44 QUARTERROUND(x, 0, 4, 8, 12) |
| 45 QUARTERROUND(x, 1, 5, 9, 13) |
| 46 QUARTERROUND(x, 2, 6, 10, 14) |
| 47 QUARTERROUND(x, 3, 7, 11, 15) |
| 48 QUARTERROUND(x, 0, 5, 10, 15) |
| 49 QUARTERROUND(x, 1, 6, 11, 12) |
| 50 QUARTERROUND(x, 2, 7, 8, 13) |
| 51 QUARTERROUND(x, 3, 4, 9, 14) |
| 52 } |
| 53 |
| 54 for (i = 0; i < 16; ++i) { |
| 55 x[i] = x[i] + input[i]; |
| 56 } |
| 57 for (i = 0; i < 16; ++i) { |
| 58 U32TO8_LITTLE(output + 4 * i, x[i]); |
| 59 } |
| 60 } |
| 61 |
| 62 static const unsigned char sigma[16] = "expand 32-byte k"; |
| 63 |
| 64 void |
| 65 ChaCha20XOR(unsigned char *out, const unsigned char *in, unsigned int inLen, |
| 66 const unsigned char key[32], const unsigned char nonce[12], |
| 67 uint32_t counter) |
| 68 { |
| 69 unsigned char block[64]; |
| 70 PRUint32 input[16]; |
| 71 unsigned int i; |
| 72 |
| 73 input[4] = U8TO32_LITTLE(key + 0); |
| 74 input[5] = U8TO32_LITTLE(key + 4); |
| 75 input[6] = U8TO32_LITTLE(key + 8); |
| 76 input[7] = U8TO32_LITTLE(key + 12); |
| 77 |
| 78 input[8] = U8TO32_LITTLE(key + 16); |
| 79 input[9] = U8TO32_LITTLE(key + 20); |
| 80 input[10] = U8TO32_LITTLE(key + 24); |
| 81 input[11] = U8TO32_LITTLE(key + 28); |
| 82 |
| 83 input[0] = U8TO32_LITTLE(sigma + 0); |
| 84 input[1] = U8TO32_LITTLE(sigma + 4); |
| 85 input[2] = U8TO32_LITTLE(sigma + 8); |
| 86 input[3] = U8TO32_LITTLE(sigma + 12); |
| 87 |
| 88 input[12] = counter; |
| 89 input[13] = U8TO32_LITTLE(nonce + 0); |
| 90 input[14] = U8TO32_LITTLE(nonce + 4); |
| 91 input[15] = U8TO32_LITTLE(nonce + 8); |
| 92 |
| 93 while (inLen >= 64) { |
| 94 ChaChaCore(block, input, 20); |
| 95 for (i = 0; i < 64; i++) { |
| 96 out[i] = in[i] ^ block[i]; |
| 97 } |
| 98 |
| 99 input[12]++; |
| 100 inLen -= 64; |
| 101 in += 64; |
| 102 out += 64; |
| 103 } |
| 104 |
| 105 if (inLen > 0) { |
| 106 ChaChaCore(block, input, 20); |
| 107 for (i = 0; i < inLen; i++) { |
| 108 out[i] = in[i] ^ block[i]; |
| 109 } |
| 110 } |
| 111 } |
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