/* crypto/rc2/rc2_cbc.c */
/* 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 "rc2.h"
#include "rc2_locl.h"

void RC2_cbc_encrypt(in, out, length, ks, iv, encrypt)
unsigned char *in;
unsigned char *out;
long length;
RC2_KEY *ks;
unsigned char *iv;
int encrypt;
	{
	register unsigned long tin0,tin1;
	register unsigned long tout0,tout1,xor0,xor1;
	register 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;
	}

void RC2_encrypt(d,key)
unsigned long *d;
RC2_KEY *key;
	{
	int i,n;
	register RC2_INT *p0,*p1;
	register 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);
	}

void RC2_decrypt(d,key)
unsigned long *d;
RC2_KEY *key;
	{
	int i,n;
	register RC2_INT *p0,*p1;
	register 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);
	}

