ede_cbcm_enc.c

/* ede_cbcm_enc.c */
/* Written by Ben Laurie <ben@algroup.co.uk> for the OpenSSL
 * project 13 Feb 1999.
 */
/* ====================================================================
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 * modification, are permitted provided that the following conditions
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 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
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 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
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 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
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 *
 */

/*

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_locl.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)
    {
    register DES_LONG tin0,tin1;
    register DES_LONG tout0,tout1,xor0,xor1,m0,m1;
    register 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
	{
	register 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