Files
GmSSL/src/chacha20.c
2021-07-13 19:21:43 +08:00

124 lines
4.0 KiB
C

/*
* Copyright (c) 2014 - 2020 The GmSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the GmSSL Project.
* (http://gmssl.org/)"
*
* 4. The name "GmSSL Project" must not be used to endorse or promote
* products derived from this software without prior written
* permission. For written permission, please contact
* guanzhi1980@gmail.com.
*
* 5. Products derived from this software may not be called "GmSSL"
* nor may "GmSSL" appear in their names without prior written
* permission of the GmSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the GmSSL Project
* (http://gmssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE GmSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE GmSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <gmssl/chacha20.h>
#include "bswap.h"
#include "rotate.h"
void chacha20_set_key(CHACHA20_STATE *state,
const unsigned char key[CHACHA20_KEY_SIZE],
const unsigned char nonce[CHACHA20_NONCE_SIZE],
uint32_t counter)
{
state->d[ 0] = 0x61707865;
state->d[ 1] = 0x3320646e;
state->d[ 2] = 0x79622d32;
state->d[ 3] = 0x6b206574;
state->d[ 4] = GETU32_LE(key );
state->d[ 5] = GETU32_LE(key + 4);
state->d[ 6] = GETU32_LE(key + 8);
state->d[ 7] = GETU32_LE(key + 12);
state->d[ 8] = GETU32_LE(key + 16);
state->d[ 9] = GETU32_LE(key + 20);
state->d[10] = GETU32_LE(key + 24);
state->d[11] = GETU32_LE(key + 28);
state->d[12] = counter;
state->d[13] = GETU32_LE(nonce);
state->d[14] = GETU32_LE(nonce + 4);
state->d[15] = GETU32_LE(nonce + 8);
}
/* quarter round */
#define QR(A, B, C, D) \
A += B; D ^= A; D = ROL32(D, 16); \
C += D; B ^= C; B = ROL32(B, 12); \
A += B; D ^= A; D = ROL32(D, 8); \
C += D; B ^= C; B = ROL32(B, 7)
/* double round on state 4x4 matrix:
* four column rounds and and four diagonal rounds
*
* 0 1 2 3
* 4 5 6 7
* 8 9 10 11
* 12 13 14 15
*
*/
#define DR(S) \
QR(S[0], S[4], S[ 8], S[12]); \
QR(S[1], S[5], S[ 9], S[13]); \
QR(S[2], S[6], S[10], S[14]); \
QR(S[3], S[7], S[11], S[15]); \
QR(S[0], S[5], S[10], S[15]); \
QR(S[1], S[6], S[11], S[12]); \
QR(S[2], S[7], S[ 8], S[13]); \
QR(S[3], S[4], S[ 9], S[14])
void chacha20_generate_keystream(CHACHA20_STATE *state, unsigned int counts, unsigned char *out)
{
uint32_t working_state[16];
int i;
while (counts-- > 0) {
memcpy(working_state, state->d, sizeof(working_state));
for (i = 0; i < 10; i++) {
DR(working_state);
}
for (i = 0; i < 16; i++) {
working_state[i] += state->d[i];
PUTU32_LE(out, working_state[i]);
out += sizeof(uint32_t);
}
state->d[12]++;
}
}