/* ====================================================================
 * Copyright (c) 2014 - 2019 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,
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * 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 <sm4.h>
#include "sms4_lcl.h"

#define L32(x)							\
	((x) ^							\
	ROL32((x),  2) ^					\
	ROL32((x), 10) ^					\
	ROL32((x), 18) ^					\
	ROL32((x), 24))

#define ROUND_SBOX(x0, x1, x2, x3, x4, i)			\
	x4 = x1 ^ x2 ^ x3 ^ *(rk + i);				\
	x4 = S32(x4);						\
	x4 = x0 ^ L32(x4)

#define ROUND_TBOX(x0, x1, x2, x3, x4, i)			\
	x4 = x1 ^ x2 ^ x3 ^ *(rk + i);				\
	t0 = ROL32(SMS4_T[(uint8_t)x4], 8);			\
	x4 >>= 8;						\
	x0 ^= t0;						\
	t0 = ROL32(SMS4_T[(uint8_t)x4], 16);			\
	x4 >>= 8;						\
	x0 ^= t0;						\
	t0 = ROL32(SMS4_T[(uint8_t)x4], 24);			\
	x4 >>= 8;						\
	x0 ^= t0;						\
	t1 = SMS4_T[x4];					\
	x4 = x0 ^ t1

#define ROUND_DBOX(x0, x1, x2, x3, x4, i)			\
	x4 = x1 ^ x2 ^ x3 ^ *(rk + i);				\
	x4 = x0 ^ SMS4_D[(uint16_t)(x4 >> 16)] ^		\
		ROL32(SMS4_D[(uint16_t)x4], 16)

#define ROUND ROUND_TBOX

void sms4_encrypt(const unsigned char in[16], unsigned char out[16], const sms4_key_t *key)
{
	const uint *rk = key->rk;
	uint x0, x1, x2, x3, x4;
	uint t0, t1;

	x0 = GETU32(in);
	x1 = GETU32(in + 4);
	x2 = GETU32(in + 8);
	x3 = GETU32(in + 12);
#define ROUND ROUND_TBOX
	ROUNDS(x0, x1, x2, x3, x4);

	PUTU32(out, x0);
	PUTU32(out + 4, x4);
	PUTU32(out + 8, x3);
	PUTU32(out + 12, x2);
}

/* caller make sure counter not overflow */
void sms4_ctr32_encrypt_blocks(const unsigned char *in, unsigned char *out,
                               int blocks, const sms4_key_t *key, const unsigned char iv[16])
{
	const uint *rk = key->rk;
	unsigned int c0 = GETU32(iv);
	unsigned int c1 = GETU32(iv + 4);
	unsigned int c2 = GETU32(iv + 8);
	unsigned int c3 = GETU32(iv + 12);
	uint x0, x1, x2, x3, x4;
	uint t0, t1;

	while (blocks--) {
		x0 = c0;
		x1 = c1;
		x2 = c2;
		x3 = c3;
		ROUNDS(x0, x1, x2, x3, x4);
		PUTU32(out, GETU32(in) ^ x0);
		PUTU32(out + 4, GETU32(in + 4) ^ x4);
		PUTU32(out + 8, GETU32(in + 8) ^ x3);
		PUTU32(out + 12, GETU32(in + 12) ^ x2);
		in += 16;
		out += 16;
		c3++;
	}
}
