ede_cbcm_enc.c

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/* ede_cbcm_enc.c */
/* Written by Ben Laurie <[email protected]> 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. 
 *
 * 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/)"
 *
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 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    [email protected].
 *
 * 5. Products derived from this software may not be called "OpenSSL"
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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
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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