/* crypto/idea/i_skey.c */
/* Copyright (C) 1995-1997 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"
#ifndef NOPROTO
static IDEA_INT inverse(unsigned int xin);
#else
static IDEA_INT inverse();
#endif
void idea_set_encrypt_key(key, ks)
unsigned char *key;
IDEA_KEY_SCHEDULE *ks;
{
int i;
register 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(ek, dk)
IDEA_KEY_SCHEDULE *ek;
IDEA_KEY_SCHEDULE *dk;
{
int r;
register 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(xin)
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);
}