/* $OpenBSD: ede_cbcm_enc.c,v 1.9 2023/07/08 07:34:34 jsing Exp $ */
/* Written by Ben Laurie <ben@algroup.co.uk> for the OpenSSL
 * project 13 Feb 1999.
 */
/* ====================================================================
 * Copyright (c) 1999 The OpenSSL 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.
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 * 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 OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL 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 OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

/*

This is an implementation of Triple DES Cipher Block Chaining with Output
Feedback Masking, by Coppersmith, Johnson and Matyas, (IBM and Certicom).

Note that there is a known attack on this by Biham and Knudsen but it takes
a lot of work:

http://www.cs.technion.ac.il/users/wwwb/cgi-bin/tr-get.cgi/1998/CS/CS0928.ps.gz

*/

#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_DESCBCM is defined */

#ifndef OPENSSL_NO_DESCBCM
#include "des_local.h"

void
DES_ede3_cbcm_encrypt(const unsigned char *in, unsigned char *out,
    long length, DES_key_schedule *ks1, DES_key_schedule *ks2,
    DES_key_schedule *ks3, DES_cblock *ivec1, DES_cblock *ivec2,
    int enc)
{
	DES_LONG tin0, tin1;
	DES_LONG tout0, tout1, xor0, xor1, m0, m1;
	long l = length;
	DES_LONG tin[2];
	unsigned char *iv1, *iv2;

	iv1 = &(*ivec1)[0];
	iv2 = &(*ivec2)[0];

	if (enc) {
		c2l(iv1, m0);
		c2l(iv1, m1);
		c2l(iv2, tout0);
		c2l(iv2, tout1);
		for (l -= 8; l >= -7; l -= 8) {
			tin[0] = m0;
			tin[1] = m1;
			DES_encrypt1(tin, ks3, 1);
			m0 = tin[0];
			m1 = tin[1];

			if (l < 0) {
				c2ln(in, tin0, tin1, l + 8);
			} else {
				c2l(in, tin0);
				c2l(in, tin1);
			}
			tin0 ^= tout0;
			tin1 ^= tout1;

			tin[0] = tin0;
			tin[1] = tin1;
			DES_encrypt1(tin, ks1, 1);
			tin[0] ^= m0;
			tin[1] ^= m1;
			DES_encrypt1(tin, ks2, 0);
			tin[0] ^= m0;
			tin[1] ^= m1;
			DES_encrypt1(tin, ks1, 1);
			tout0 = tin[0];
			tout1 = tin[1];

			l2c(tout0, out);
			l2c(tout1, out);
		}
		iv1 = &(*ivec1)[0];
		l2c(m0, iv1);
		l2c(m1, iv1);

		iv2 = &(*ivec2)[0];
		l2c(tout0, iv2);
		l2c(tout1, iv2);
	} else {
		DES_LONG t0, t1;

		c2l(iv1, m0);
		c2l(iv1, m1);
		c2l(iv2, xor0);
		c2l(iv2, xor1);
		for (l -= 8; l >= -7; l -= 8) {
			tin[0] = m0;
			tin[1] = m1;
			DES_encrypt1(tin, ks3, 1);
			m0 = tin[0];
			m1 = tin[1];

			c2l(in, tin0);
			c2l(in, tin1);

			t0 = tin0;
			t1 = tin1;

			tin[0] = tin0;
			tin[1] = tin1;
			DES_encrypt1(tin, ks1, 0);
			tin[0] ^= m0;
			tin[1] ^= m1;
			DES_encrypt1(tin, ks2, 1);
			tin[0] ^= m0;
			tin[1] ^= m1;
			DES_encrypt1(tin, ks1, 0);
			tout0 = tin[0];
			tout1 = tin[1];

			tout0 ^= xor0;
			tout1 ^= xor1;
			if (l < 0) {
				l2cn(tout0, tout1, out, l + 8);
			} else {
				l2c(tout0, out);
				l2c(tout1, out);
			}
			xor0 = t0;
			xor1 = t1;
		}

		iv1 = &(*ivec1)[0];
		l2c(m0, iv1);
		l2c(m1, iv1);

		iv2 = &(*ivec2)[0];
		l2c(xor0, iv2);
		l2c(xor1, iv2);
	}
	tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
	tin[0] = tin[1] = 0;
}
#endif