i_cbc.c

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/* crypto/idea/i_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 "idea.h"
#include "idea_lcl.h"

void idea_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
             IDEA_KEY_SCHEDULE *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)
                {
                n2l(iv,tout0);
                n2l(iv,tout1);
                iv-=8;
                for (l-=8; l>=0; l-=8)
                        {
                        n2l(in,tin0);
                        n2l(in,tin1);
                        tin0^=tout0;
                        tin1^=tout1;
                        tin[0]=tin0;
                        tin[1]=tin1;
                        idea_encrypt(tin,ks);
                        tout0=tin[0]; l2n(tout0,out);
                        tout1=tin[1]; l2n(tout1,out);
                        }
                if (l != -8)
                        {
                        n2ln(in,tin0,tin1,l+8);
                        tin0^=tout0;
                        tin1^=tout1;
                        tin[0]=tin0;
                        tin[1]=tin1;
                        idea_encrypt(tin,ks);
                        tout0=tin[0]; l2n(tout0,out);
                        tout1=tin[1]; l2n(tout1,out);
                        }
                l2n(tout0,iv);
                l2n(tout1,iv);
                }
        else
                {
                n2l(iv,xor0);
                n2l(iv,xor1);
                iv-=8;
                for (l-=8; l>=0; l-=8)
                        {
                        n2l(in,tin0); tin[0]=tin0;
                        n2l(in,tin1); tin[1]=tin1;
                        idea_encrypt(tin,ks);
                        tout0=tin[0]^xor0;
                        tout1=tin[1]^xor1;
                        l2n(tout0,out);
                        l2n(tout1,out);
                        xor0=tin0;
                        xor1=tin1;
                        }
                if (l != -8)
                        {
                        n2l(in,tin0); tin[0]=tin0;
                        n2l(in,tin1); tin[1]=tin1;
                        idea_encrypt(tin,ks);
                        tout0=tin[0]^xor0;
                        tout1=tin[1]^xor1;
                        l2nn(tout0,tout1,out,l+8);
                        xor0=tin0;
                        xor1=tin1;
                        }
                l2n(xor0,iv);
                l2n(xor1,iv);
                }
        tin0=tin1=tout0=tout1=xor0=xor1=0;
        tin[0]=tin[1]=0;
        }

void idea_encrypt(unsigned long *d, IDEA_KEY_SCHEDULE *key)
        {
        register IDEA_INT *p;
        register unsigned long x1,x2,x3,x4,t0,t1,ul;

        x2=d[0];
        x1=(x2>>16);
        x4=d[1];
        x3=(x4>>16);

        p= &(key->data[0][0]);

        E_IDEA(0);
        E_IDEA(1);
        E_IDEA(2);
        E_IDEA(3);
        E_IDEA(4);
        E_IDEA(5);
        E_IDEA(6);
        E_IDEA(7);

        x1&=0xffff;
        idea_mul(x1,x1,*p,ul); p++;

        t0= x3+ *(p++);
        t1= x2+ *(p++);

        x4&=0xffff;
        idea_mul(x4,x4,*p,ul);

        d[0]=(t0&0xffff)|((x1&0xffff)<<16);
        d[1]=(x4&0xffff)|((t1&0xffff)<<16);
        }