/* $OpenBSD: xcbc_enc.c,v 1.12 2023/07/08 07:34:34 jsing Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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 acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include "des_local.h"

/* RSA's DESX */

void
DES_xcbc_encrypt(const unsigned char *in, unsigned char *out,
    long length, DES_key_schedule *schedule,
    DES_cblock *ivec, const_DES_cblock *inw,
    const_DES_cblock *outw, int enc)
{
	DES_LONG tin0, tin1;
	DES_LONG tout0, tout1, xor0, xor1;
	DES_LONG inW0, inW1, outW0, outW1;
	const unsigned char *in2;
	long l = length;
	DES_LONG tin[2];
	unsigned char *iv;

	in2 = &(*inw)[0];
	c2l(in2, inW0);
	c2l(in2, inW1);
	in2 = &(*outw)[0];
	c2l(in2, outW0);
	c2l(in2, outW1);

	iv = &(*ivec)[0];

	if (enc) {
		c2l(iv, tout0);
		c2l(iv, tout1);
		for (l -= 8; l >= 0; l -= 8) {
			c2l(in, tin0);
			c2l(in, tin1);
			tin0 ^= tout0 ^ inW0;
			tin[0] = tin0;
			tin1 ^= tout1 ^ inW1;
			tin[1] = tin1;
			DES_encrypt1(tin, schedule, DES_ENCRYPT);
			tout0 = tin[0] ^ outW0;
			l2c(tout0, out);
			tout1 = tin[1] ^ outW1;
			l2c(tout1, out);
		}
		if (l != -8) {
			c2ln(in, tin0, tin1, l + 8);
			tin0 ^= tout0 ^ inW0;
			tin[0] = tin0;
			tin1 ^= tout1 ^ inW1;
			tin[1] = tin1;
			DES_encrypt1(tin, schedule, DES_ENCRYPT);
			tout0 = tin[0] ^ outW0;
			l2c(tout0, out);
			tout1 = tin[1] ^ outW1;
			l2c(tout1, out);
		}
		iv = &(*ivec)[0];
		l2c(tout0, iv);
		l2c(tout1, iv);
	} else {
		c2l(iv, xor0);
		c2l(iv, xor1);
		for (l -= 8; l > 0; l -= 8) {
			c2l(in, tin0);
			tin[0] = tin0 ^ outW0;
			c2l(in, tin1);
			tin[1] = tin1 ^ outW1;
			DES_encrypt1(tin, schedule, DES_DECRYPT);
			tout0 = tin[0] ^ xor0 ^ inW0;
			tout1 = tin[1] ^ xor1 ^ inW1;
			l2c(tout0, out);
			l2c(tout1, out);
			xor0 = tin0;
			xor1 = tin1;
		}
		if (l != -8) {
			c2l(in, tin0);
			tin[0] = tin0 ^ outW0;
			c2l(in, tin1);
			tin[1] = tin1 ^ outW1;
			DES_encrypt1(tin, schedule, DES_DECRYPT);
			tout0 = tin[0] ^ xor0 ^ inW0;
			tout1 = tin[1] ^ xor1 ^ inW1;
			l2cn(tout0, tout1, out, l + 8);
			xor0 = tin0;
			xor1 = tin1;
		}

		iv = &(*ivec)[0];
		l2c(xor0, iv);
		l2c(xor1, iv);
	}
	tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
	inW0 = inW1 = outW0 = outW1 = 0;
	tin[0] = tin[1] = 0;
}
