mirror of https://github.com/wolfSSL/wolfssl.git
251 lines
6.0 KiB
C
251 lines
6.0 KiB
C
/* chacha.c
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*
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* Copyright (C) 2006-2014 wolfSSL Inc.
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*
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* This file is part of CyaSSL.
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*
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* CyaSSL is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* CyaSSL is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*
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* based from
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* chacha-ref.c version 20080118
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* D. J. Bernstein
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* Public domain.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <cyassl/ctaocrypt/settings.h>
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#ifdef HAVE_CHACHA
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#include <cyassl/ctaocrypt/chacha.h>
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#include <cyassl/ctaocrypt/error-crypt.h>
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#include <cyassl/ctaocrypt/logging.h>
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#ifdef NO_INLINE
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#include <cyassl/ctaocrypt/misc.h>
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#else
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#include <ctaocrypt/src/misc.c>
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#endif
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#ifdef CHACHA_AEAD_TEST
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#include <stdio.h>
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#endif
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#ifdef BIG_ENDIAN_ORDER
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#define LITTLE32(x) ByteReverseWord32(x)
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#else
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#define LITTLE32(x) (x)
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#endif
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/* Number of rounds */
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#define ROUNDS 20
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#define U32C(v) (v##U)
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#define U32V(v) ((word32)(v) & U32C(0xFFFFFFFF))
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#define U8TO32_LITTLE(p) LITTLE32(((word32*)(p))[0])
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#define ROTATE(v,c) rotlFixed(v, c)
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#define XOR(v,w) ((v) ^ (w))
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#define PLUS(v,w) (U32V((v) + (w)))
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#define PLUSONE(v) (PLUS((v),1))
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#define QUARTERROUND(a,b,c,d) \
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x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]),16); \
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x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]),12); \
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x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]), 8); \
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x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]), 7);
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/**
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* Set up iv(nonce). Earlier versions used 64 bits instead of 96, this version
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* uses the typical AEAD 96 bit nonce and can do record sizes of 256 GB.
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*/
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int Chacha_SetIV(ChaCha* ctx, const byte* inIv, word32 counter)
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{
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word32 temp[3]; /* used for alignment of memory */
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XMEMSET(temp, 0, 12);
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if (ctx == NULL)
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return BAD_FUNC_ARG;
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#ifdef CHACHA_AEAD_TEST
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word32 i;
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printf("NONCE : ");
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for (i = 0; i < 12; i++) {
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printf("%02x", inIv[i]);
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}
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printf("\n\n");
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#endif
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XMEMCPY(temp, inIv, 12);
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ctx->X[12] = counter; /* block counter */
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ctx->X[13] = temp[0]; /* fixed variable from nonce */
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ctx->X[14] = temp[1]; /* counter from nonce */
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ctx->X[15] = temp[2]; /* counter from nonce */
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return 0;
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}
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/* "expand 32-byte k" as unsigned 32 byte */
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static const word32 sigma[4] = {0x61707865, 0x3320646e, 0x79622d32, 0x6b206574};
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/* "expand 16-byte k" as unsigned 16 byte */
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static const word32 tau[4] = {0x61707865, 0x3120646e, 0x79622d36, 0x6b206574};
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/**
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* Key setup. 8 word iv (nonce)
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*/
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int Chacha_SetKey(ChaCha* ctx, const byte* key, word32 keySz)
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{
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const word32* constants;
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const byte* k;
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if (ctx == NULL)
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return BAD_FUNC_ARG;
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#ifdef XSTREAM_ALIGN
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word32 alignKey[keySz / 4];
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if ((word)key % 4) {
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CYASSL_MSG("ChachaSetKey unaligned key");
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XMEMCPY(alignKey, key, sizeof(alignKey));
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k = (byte*)alignKey;
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}
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else {
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k = key;
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}
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#else
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k = key;
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#endif /* XSTREAM_ALIGN */
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#ifdef CHACHA_AEAD_TEST
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word32 i;
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printf("ChaCha key used :\n");
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for (i = 0; i < keySz; i++) {
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printf("%02x", key[i]);
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if ((i + 1) % 8 == 0)
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printf("\n");
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}
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printf("\n\n");
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#endif
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ctx->X[4] = U8TO32_LITTLE(k + 0);
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ctx->X[5] = U8TO32_LITTLE(k + 4);
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ctx->X[6] = U8TO32_LITTLE(k + 8);
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ctx->X[7] = U8TO32_LITTLE(k + 12);
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if (keySz == 32) {
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k += 16;
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constants = sigma;
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}
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else {
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/* key size of 128 */
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if (keySz != 16)
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return BAD_FUNC_ARG;
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constants = tau;
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}
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ctx->X[ 8] = U8TO32_LITTLE(k + 0);
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ctx->X[ 9] = U8TO32_LITTLE(k + 4);
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ctx->X[10] = U8TO32_LITTLE(k + 8);
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ctx->X[11] = U8TO32_LITTLE(k + 12);
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ctx->X[ 0] = U8TO32_LITTLE(constants + 0);
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ctx->X[ 1] = U8TO32_LITTLE(constants + 1);
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ctx->X[ 2] = U8TO32_LITTLE(constants + 2);
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ctx->X[ 3] = U8TO32_LITTLE(constants + 3);
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return 0;
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}
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/**
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* Converts word into bytes with rotations having been done.
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*/
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static INLINE void Chacha_wordtobyte(word32 output[16], const word32 input[16])
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{
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word32 x[16];
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word32 i;
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for (i = 0; i < 16; i++) {
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x[i] = input[i];
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}
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for (i = (ROUNDS); i > 0; i -= 2) {
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QUARTERROUND(0, 4, 8, 12)
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QUARTERROUND(1, 5, 9, 13)
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QUARTERROUND(2, 6, 10, 14)
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QUARTERROUND(3, 7, 11, 15)
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QUARTERROUND(0, 5, 10, 15)
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QUARTERROUND(1, 6, 11, 12)
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QUARTERROUND(2, 7, 8, 13)
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QUARTERROUND(3, 4, 9, 14)
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}
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for (i = 0; i < 16; i++) {
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x[i] = PLUS(x[i], input[i]);
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}
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for (i = 0; i < 16; i++) {
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output[i] = LITTLE32(x[i]);
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}
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}
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/**
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* Encrypt a stream of bytes
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*/
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static void Chacha_encrypt_bytes(ChaCha* ctx, const byte* m, byte* c,
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word32 bytes)
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{
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byte* output;
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word32 temp[16]; /* used to make sure aligned */
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word32 i;
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output = (byte*)temp;
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if (!bytes) return;
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for (;;) {
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Chacha_wordtobyte(temp, ctx->X);
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ctx->X[12] = PLUSONE(ctx->X[12]);
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if (bytes <= 64) {
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for (i = 0; i < bytes; ++i) {
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c[i] = m[i] ^ output[i];
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}
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return;
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}
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for (i = 0; i < 64; ++i) {
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c[i] = m[i] ^ output[i];
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}
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bytes -= 64;
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c += 64;
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m += 64;
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}
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}
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/**
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* API to encrypt/decrypt a message of any size.
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*/
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int Chacha_Process(ChaCha* ctx, byte* output, const byte* input, word32 msglen)
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{
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if (ctx == NULL)
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return BAD_FUNC_ARG;
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Chacha_encrypt_bytes(ctx, input, output, msglen);
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return 0;
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}
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#endif /* HAVE_CHACHA*/
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