/* $OpenBSD: i_skey.c,v 1.4 2014/10/28 07:35:58 jsg 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/crypto.h>

#include <openssl/idea.h>

#include "idea_lcl.h"

static IDEA_INT inverse(unsigned int xin);

void idea_set_encrypt_key(const unsigned char *key, IDEA_KEY_SCHEDULE *ks)

  {

  int i;

  IDEA_INT *kt,*kf,r0,r1,r2;

  kt= &(ks->data[0][0]);

  n2s(key,kt[0]); n2s(key,kt[1]); n2s(key,kt[2]); n2s(key,kt[3]);

  n2s(key,kt[4]); n2s(key,kt[5]); n2s(key,kt[6]); n2s(key,kt[7]);

  kf=kt;

  kt+=8;

  for (i=0; i<6; i++)

    {

    r2= kf[1];

    r1= kf[2];

    *(kt++)= ((r2<<9) | (r1>>7))&0xffff;

    r0= kf[3];

    *(kt++)= ((r1<<9) | (r0>>7))&0xffff;

    r1= kf[4];

    *(kt++)= ((r0<<9) | (r1>>7))&0xffff;

    r0= kf[5];

    *(kt++)= ((r1<<9) | (r0>>7))&0xffff;

    r1= kf[6];

    *(kt++)= ((r0<<9) | (r1>>7))&0xffff;

    r0= kf[7];

    *(kt++)= ((r1<<9) | (r0>>7))&0xffff;

    r1= kf[0];

    if (i >= 5) break;

    *(kt++)= ((r0<<9) | (r1>>7))&0xffff;

    *(kt++)= ((r1<<9) | (r2>>7))&0xffff;

    kf+=8;

    }

  }

void idea_set_decrypt_key(IDEA_KEY_SCHEDULE *ek, IDEA_KEY_SCHEDULE *dk)

  {

  int r;

  IDEA_INT *fp,*tp,t;

  tp= &(dk->data[0][0]);

  fp= &(ek->data[8][0]);

  for (r=0; r<9; r++)

    {

    *(tp++)=inverse(fp[0]);

    *(tp++)=((int)(0x10000L-fp[2])&0xffff);

    *(tp++)=((int)(0x10000L-fp[1])&0xffff);

    *(tp++)=inverse(fp[3]);

    if (r == 8) break;

    fp-=6;

    *(tp++)=fp[4];

    *(tp++)=fp[5];

    }

  tp= &(dk->data[0][0]);

  t=tp[1];

  tp[1]=tp[2];

  tp[2]=t;

  t=tp[49];

  tp[49]=tp[50];

  tp[50]=t;

  }

/* taken directly from the 'paper' I'll have a look at it later */

static IDEA_INT inverse(unsigned int xin)

  {

  long n1,n2,q,r,b1,b2,t;

  if (xin == 0)

    b2=0;

  else

    {

    n1=0x10001;

    n2=xin;

    b2=1;

    b1=0;

    do  {

      r=(n1%n2);

      q=(n1-r)/n2;

      if (r == 0)

        { if (b2 < 0) b2=0x10001+b2; }

      else

        {

        n1=n2;

        n2=r;

        t=b2;

        b2=b1-q*b2;

        b1=t;

        }

      } while (r != 0);

    }

  return((IDEA_INT)b2);

  }