mirror of
https://github.com/rn10950/RetroZilla.git
synced 2024-11-14 19:50:12 +01:00
112 lines
3.3 KiB
C
112 lines
3.3 KiB
C
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* Adopted from the public domain code in NaCl by djb. */
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#include <string.h>
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#include <stdio.h>
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#include "prtypes.h"
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#include "secport.h"
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#include "chacha20.h"
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#if defined(_MSC_VER)
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#pragma intrinsic(_lrotl)
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#define ROTL32(x, n) _lrotl(x, n)
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#else
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#define ROTL32(x, n) ((x << n) | (x >> ((8 * sizeof x) - n)))
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#endif
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#define ROTATE(v, c) ROTL32((v), (c))
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#define U32TO8_LITTLE(p, v) \
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{ (p)[0] = ((v) ) & 0xff; (p)[1] = ((v) >> 8) & 0xff; \
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(p)[2] = ((v) >> 16) & 0xff; (p)[3] = ((v) >> 24) & 0xff; }
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#define U8TO32_LITTLE(p) \
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(((PRUint32)((p)[0]) ) | ((PRUint32)((p)[1]) << 8) | \
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((PRUint32)((p)[2]) << 16) | ((PRUint32)((p)[3]) << 24))
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#define QUARTERROUND(x, a, b, c, d) \
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x[a] = x[a] + x[b]; x[d] = ROTATE(x[d] ^ x[a], 16); \
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x[c] = x[c] + x[d]; x[b] = ROTATE(x[b] ^ x[c], 12); \
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x[a] = x[a] + x[b]; x[d] = ROTATE(x[d] ^ x[a], 8); \
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x[c] = x[c] + x[d]; x[b] = ROTATE(x[b] ^ x[c], 7);
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static void
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ChaChaCore(unsigned char output[64], const PRUint32 input[16], int num_rounds)
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{
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PRUint32 x[16];
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int i;
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PORT_Memcpy(x, input, sizeof(PRUint32) * 16);
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for (i = num_rounds; i > 0; i -= 2) {
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QUARTERROUND(x, 0, 4, 8, 12)
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QUARTERROUND(x, 1, 5, 9, 13)
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QUARTERROUND(x, 2, 6, 10, 14)
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QUARTERROUND(x, 3, 7, 11, 15)
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QUARTERROUND(x, 0, 5, 10, 15)
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QUARTERROUND(x, 1, 6, 11, 12)
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QUARTERROUND(x, 2, 7, 8, 13)
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QUARTERROUND(x, 3, 4, 9, 14)
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}
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for (i = 0; i < 16; ++i) {
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x[i] = x[i] + input[i];
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}
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for (i = 0; i < 16; ++i) {
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U32TO8_LITTLE(output + 4 * i, x[i]);
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}
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}
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static const unsigned char sigma[16] = "expand 32-byte k";
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void
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ChaCha20XOR(unsigned char *out, const unsigned char *in, unsigned int inLen,
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const unsigned char key[32], const unsigned char nonce[12],
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uint32_t counter)
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{
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unsigned char block[64];
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PRUint32 input[16];
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unsigned int i;
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input[4] = U8TO32_LITTLE(key + 0);
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input[5] = U8TO32_LITTLE(key + 4);
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input[6] = U8TO32_LITTLE(key + 8);
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input[7] = U8TO32_LITTLE(key + 12);
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input[8] = U8TO32_LITTLE(key + 16);
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input[9] = U8TO32_LITTLE(key + 20);
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input[10] = U8TO32_LITTLE(key + 24);
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input[11] = U8TO32_LITTLE(key + 28);
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input[0] = U8TO32_LITTLE(sigma + 0);
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input[1] = U8TO32_LITTLE(sigma + 4);
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input[2] = U8TO32_LITTLE(sigma + 8);
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input[3] = U8TO32_LITTLE(sigma + 12);
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input[12] = counter;
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input[13] = U8TO32_LITTLE(nonce + 0);
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input[14] = U8TO32_LITTLE(nonce + 4);
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input[15] = U8TO32_LITTLE(nonce + 8);
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while (inLen >= 64) {
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ChaChaCore(block, input, 20);
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for (i = 0; i < 64; i++) {
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out[i] = in[i] ^ block[i];
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}
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input[12]++;
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inLen -= 64;
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in += 64;
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out += 64;
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}
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if (inLen > 0) {
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ChaChaCore(block, input, 20);
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for (i = 0; i < inLen; i++) {
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out[i] = in[i] ^ block[i];
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}
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}
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}
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