/* crypto/idea/i_skey.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
#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;
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(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(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);
}