1  //FIXME Not checked on threadsafety yet; after checking please remove this line


2  /* crypto/idea/i_skey.c */


3  /* Copyright (C) 19951998 Eric Young (eay@cryptsoft.com)


4  * All rights reserved.


5  *


6  * This package is an SSL implementation written


7  * by Eric Young (eay@cryptsoft.com).


8  * The implementation was written so as to conform with Netscapes SSL.


9  *


10  * This library is free for commercial and noncommercial use as long as


11  * the following conditions are aheared to. The following conditions


12  * apply to all code found in this distribution, be it the RC4, RSA,


13  * lhash, DES, etc., code; not just the SSL code. The SSL documentation


14  * included with this distribution is covered by the same copyright terms


15  * except that the holder is Tim Hudson (tjh@cryptsoft.com).


16  *


17  * Copyright remains Eric Young's, and as such any Copyright notices in


18  * the code are not to be removed.


19  * If this package is used in a product, Eric Young should be given attribution


20  * as the author of the parts of the library used.


21  * This can be in the form of a textual message at program startup or


22  * in documentation (online or textual) provided with the package.


23  *


24  * Redistribution and use in source and binary forms, with or without


25  * modification, are permitted provided that the following conditions


26  * are met:


27  * 1. Redistributions of source code must retain the copyright


28  * notice, this list of conditions and the following disclaimer.


29  * 2. Redistributions in binary form must reproduce the above copyright


30  * notice, this list of conditions and the following disclaimer in the


31  * documentation and/or other materials provided with the distribution.


32  * 3. All advertising materials mentioning features or use of this software


33  * must display the following acknowledgement:


34  * "This product includes cryptographic software written by


35  * Eric Young (eay@cryptsoft.com)"


36  * The word 'cryptographic' can be left out if the rouines from the library


37  * being used are not cryptographic related :).


38  * 4. If you include any Windows specific code (or a derivative thereof) from


39  * the apps directory (application code) you must include an acknowledgement:


40  * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"


41  *


42  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND


43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE


44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE


45  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE


46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL


47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS


48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)


49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT


50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY


51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF


52  * SUCH DAMAGE.


53  *


54  * The licence and distribution terms for any publically available version or


55  * derivative of this code cannot be changed. i.e. this code cannot simply be


56  * copied and put under another distribution licence


57  * [including the GNU Public Licence.]


58  */


59 


60  #include "idea.h"


61  #include "idea_lcl.h"


62 


63  static IDEA_INT inverse(unsigned int xin);


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


65  {


66  int i;


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


68 


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


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


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


72 


73  kf=kt;


74  kt+=8;


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


76  {


77  r2= kf[1];


78  r1= kf[2];


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


80  r0= kf[3];


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


82  r1= kf[4];


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


84  r0= kf[5];


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


86  r1= kf[6];


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


88  r0= kf[7];


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


90  r1= kf[0];


91  if (i >= 5) break;


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


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


94  kf+=8;


95  }


96  }


97 


98  void idea_set_decrypt_key(IDEA_KEY_SCHEDULE *ek, IDEA_KEY_SCHEDULE *dk)


99  {


100  int r;


101  register IDEA_INT *fp,*tp,t;


102 


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


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


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


106  {


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


108  *(tp++)=((int)(0x10000Lfp[2])&0xffff);


109  *(tp++)=((int)(0x10000Lfp[1])&0xffff);


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


111  if (r == 8) break;


112  fp=6;


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


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


115  }


116 


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


118  t=tp[1];


119  tp[1]=tp[2];


120  tp[2]=t;


121 


122  t=tp[49];


123  tp[49]=tp[50];


124  tp[50]=t;


125  }


126 


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


128  static IDEA_INT inverse(unsigned int xin)


129  {


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


131 


132  if (xin == 0)


133  b2=0;


134  else


135  {


136  n1=0x10001;


137  n2=xin;


138  b2=1;


139  b1=0;


140 


141  do {


142  r=(n1%n2);


143  q=(n1r)/n2;


144  if (r == 0)


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


146  else


147  {


148  n1=n2;


149  n2=r;


150  t=b2;


151  b2=b1q*b2;


152  b1=t;


153  }


154  } while (r != 0);


155  }


156  return((IDEA_INT)b2);


157  }

