| /* This Source Code Form is subject to the terms of the Mozilla Public |
| * License, v. 2.0. If a copy of the MPL was not distributed with this |
| * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| |
| /* Adopted from the public domain code in NaCl by djb. */ |
| |
| #include <string.h> |
| #include <stdio.h> |
| |
| #include "prtypes.h" |
| #include "secport.h" |
| #include "chacha20.h" |
| |
| #if defined(_MSC_VER) |
| #pragma intrinsic(_lrotl) |
| #define ROTL32(x, n) _lrotl(x, n) |
| #else |
| #define ROTL32(x, n) ((x << n) | (x >> ((8 * sizeof x) - n))) |
| #endif |
| |
| #define ROTATE(v, c) ROTL32((v), (c)) |
| |
| #define U32TO8_LITTLE(p, v) \ |
| { (p)[0] = ((v) ) & 0xff; (p)[1] = ((v) >> 8) & 0xff; \ |
| (p)[2] = ((v) >> 16) & 0xff; (p)[3] = ((v) >> 24) & 0xff; } |
| #define U8TO32_LITTLE(p) \ |
| (((PRUint32)((p)[0]) ) | ((PRUint32)((p)[1]) << 8) | \ |
| ((PRUint32)((p)[2]) << 16) | ((PRUint32)((p)[3]) << 24)) |
| |
| #define QUARTERROUND(x, a, b, c, d) \ |
| x[a] = x[a] + x[b]; x[d] = ROTATE(x[d] ^ x[a], 16); \ |
| x[c] = x[c] + x[d]; x[b] = ROTATE(x[b] ^ x[c], 12); \ |
| x[a] = x[a] + x[b]; x[d] = ROTATE(x[d] ^ x[a], 8); \ |
| x[c] = x[c] + x[d]; x[b] = ROTATE(x[b] ^ x[c], 7); |
| |
| static void |
| ChaChaCore(unsigned char output[64], const PRUint32 input[16], int num_rounds) |
| { |
| PRUint32 x[16]; |
| int i; |
| |
| PORT_Memcpy(x, input, sizeof(PRUint32) * 16); |
| for (i = num_rounds; i > 0; i -= 2) { |
| QUARTERROUND(x, 0, 4, 8, 12) |
| QUARTERROUND(x, 1, 5, 9, 13) |
| QUARTERROUND(x, 2, 6, 10, 14) |
| QUARTERROUND(x, 3, 7, 11, 15) |
| QUARTERROUND(x, 0, 5, 10, 15) |
| QUARTERROUND(x, 1, 6, 11, 12) |
| QUARTERROUND(x, 2, 7, 8, 13) |
| QUARTERROUND(x, 3, 4, 9, 14) |
| } |
| |
| for (i = 0; i < 16; ++i) { |
| x[i] = x[i] + input[i]; |
| } |
| for (i = 0; i < 16; ++i) { |
| U32TO8_LITTLE(output + 4 * i, x[i]); |
| } |
| } |
| |
| static const unsigned char sigma[16] = "expand 32-byte k"; |
| |
| void |
| ChaCha20XOR(unsigned char *out, const unsigned char *in, unsigned int inLen, |
| const unsigned char key[32], const unsigned char nonce[12], |
| uint32_t counter) |
| { |
| unsigned char block[64]; |
| PRUint32 input[16]; |
| unsigned int i; |
| |
| 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[0] = U8TO32_LITTLE(sigma + 0); |
| input[1] = U8TO32_LITTLE(sigma + 4); |
| input[2] = U8TO32_LITTLE(sigma + 8); |
| input[3] = U8TO32_LITTLE(sigma + 12); |
| |
| input[12] = counter; |
| input[13] = U8TO32_LITTLE(nonce + 0); |
| input[14] = U8TO32_LITTLE(nonce + 4); |
| input[15] = U8TO32_LITTLE(nonce + 8); |
| |
| while (inLen >= 64) { |
| ChaChaCore(block, input, 20); |
| for (i = 0; i < 64; i++) { |
| out[i] = in[i] ^ block[i]; |
| } |
| |
| input[12]++; |
| inLen -= 64; |
| in += 64; |
| out += 64; |
| } |
| |
| if (inLen > 0) { |
| ChaChaCore(block, input, 20); |
| for (i = 0; i < inLen; i++) { |
| out[i] = in[i] ^ block[i]; |
| } |
| } |
| } |