xref: /openbsd/lib/libcrypto/rc2/rc2_cbc.c (revision 4a925a6a)

/* $OpenBSD: rc2_cbc.c,v 1.8 2023/07/07 13:40:44 beck 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 <openssl/rc2.h>
#include "rc2_local.h"

void
RC2_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
    RC2_KEY *ks, unsigned char *iv, int encrypt)
{
	unsigned long tin0, tin1;
	unsigned long tout0, tout1, xor0, xor1;
	long l = length;
	unsigned long tin[2];

	if (encrypt) {
		c2l(iv, tout0);
		c2l(iv, tout1);
		iv -= 8;
		for (l -= 8; l >= 0; l -= 8)
		{
			c2l(in, tin0);
			c2l(in, tin1);
			tin0 ^= tout0;
			tin1 ^= tout1;
			tin[0] = tin0;
			tin[1] = tin1;
			RC2_encrypt(tin, ks);
			tout0 = tin[0];
			l2c(tout0, out);
			tout1 = tin[1];
			l2c(tout1, out);
		}
		if (l != -8) {
			c2ln(in, tin0, tin1, l + 8);
			tin0 ^= tout0;
			tin1 ^= tout1;
			tin[0] = tin0;
			tin[1] = tin1;
			RC2_encrypt(tin, ks);
			tout0 = tin[0];
			l2c(tout0, out);
			tout1 = tin[1];
			l2c(tout1, out);
		}
		l2c(tout0, iv);
		l2c(tout1, iv);
	} else {
		c2l(iv, xor0);
		c2l(iv, xor1);
		iv -= 8;
		for (l -= 8; l >= 0; l -= 8)
		{
			c2l(in, tin0);
			tin[0] = tin0;
			c2l(in, tin1);
			tin[1] = tin1;
			RC2_decrypt(tin, ks);
			tout0 = tin[0] ^ xor0;
			tout1 = tin[1] ^ xor1;
			l2c(tout0, out);
			l2c(tout1, out);
			xor0 = tin0;
			xor1 = tin1;
		}
		if (l != -8) {
			c2l(in, tin0);
			tin[0] = tin0;
			c2l(in, tin1);
			tin[1] = tin1;
			RC2_decrypt(tin, ks);
			tout0 = tin[0] ^ xor0;
			tout1 = tin[1] ^ xor1;
			l2cn(tout0, tout1, out, l + 8);
			xor0 = tin0;
			xor1 = tin1;
		}
		l2c(xor0, iv);
		l2c(xor1, iv);
	}
	tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
	tin[0] = tin[1] = 0;
}
LCRYPTO_ALIAS(RC2_cbc_encrypt);

void
RC2_encrypt(unsigned long *d, RC2_KEY *key)
{
	int i, n;
	RC2_INT *p0, *p1;
	RC2_INT x0, x1, x2, x3, t;
	unsigned long l;

	l = d[0];
	x0 = (RC2_INT)l & 0xffff;
	x1 = (RC2_INT)(l >> 16L);
	l = d[1];
	x2 = (RC2_INT)l & 0xffff;
	x3 = (RC2_INT)(l >> 16L);

	n = 3;
	i = 5;

	p0 = p1 = &(key->data[0]);
	for (;;) {
		t = (x0 + (x1 & ~x3) + (x2 & x3) + *(p0++)) & 0xffff;
		x0 = (t << 1)|(t >> 15);
		t = (x1 + (x2 & ~x0) + (x3 & x0) + *(p0++)) & 0xffff;
		x1 = (t << 2)|(t >> 14);
		t = (x2 + (x3 & ~x1) + (x0 & x1) + *(p0++)) & 0xffff;
		x2 = (t << 3)|(t >> 13);
		t = (x3 + (x0 & ~x2) + (x1 & x2) + *(p0++)) & 0xffff;
		x3 = (t << 5)|(t >> 11);

		if (--i == 0) {
			if (--n == 0)
				break;
			i = (n == 2) ? 6 : 5;

			x0 += p1[x3 & 0x3f];
			x1 += p1[x0 & 0x3f];
			x2 += p1[x1 & 0x3f];
			x3 += p1[x2 & 0x3f];
		}
	}

	d[0] = (unsigned long)(x0 & 0xffff)|((unsigned long)(x1 & 0xffff) <<
	    16L);
	d[1] = (unsigned long)(x2 & 0xffff)|((unsigned long)(x3 & 0xffff) <<
	    16L);
}
LCRYPTO_ALIAS(RC2_encrypt);

void
RC2_decrypt(unsigned long *d, RC2_KEY *key)
{
	int i, n;
	RC2_INT *p0, *p1;
	RC2_INT x0, x1, x2, x3, t;
	unsigned long l;

	l = d[0];
	x0 = (RC2_INT)l & 0xffff;
	x1 = (RC2_INT)(l >> 16L);
	l = d[1];
	x2 = (RC2_INT)l & 0xffff;
	x3 = (RC2_INT)(l >> 16L);

	n = 3;
	i = 5;

	p0 = &(key->data[63]);
	p1 = &(key->data[0]);
	for (;;) {
		t = ((x3 << 11)|(x3 >> 5)) & 0xffff;
		x3 = (t - (x0 & ~x2) - (x1 & x2) - *(p0--)) & 0xffff;
		t = ((x2 << 13)|(x2 >> 3)) & 0xffff;
		x2 = (t - (x3 & ~x1) - (x0 & x1) - *(p0--)) & 0xffff;
		t = ((x1 << 14)|(x1 >> 2)) & 0xffff;
		x1 = (t - (x2 & ~x0) - (x3 & x0) - *(p0--)) & 0xffff;
		t = ((x0 << 15)|(x0 >> 1)) & 0xffff;
		x0 = (t - (x1 & ~x3) - (x2 & x3) - *(p0--)) & 0xffff;

		if (--i == 0) {
			if (--n == 0)
				break;
			i = (n == 2) ? 6 : 5;

			x3 = (x3 - p1[x2 & 0x3f]) & 0xffff;
			x2 = (x2 - p1[x1 & 0x3f]) & 0xffff;
			x1 = (x1 - p1[x0 & 0x3f]) & 0xffff;
			x0 = (x0 - p1[x3 & 0x3f]) & 0xffff;
		}
	}

	d[0] = (unsigned long)(x0 & 0xffff)|((unsigned long)(x1 & 0xffff) <<
	    16L);
	d[1] = (unsigned long)(x2 & 0xffff)|((unsigned long)(x3 & 0xffff) <<
	    16L);
}
LCRYPTO_ALIAS(RC2_decrypt);