1/* crypto/idea/i_skey.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59#include <openssl/idea.h>
60#include "idea_lcl.h"
61
62static IDEA_INT inverse(unsigned int xin);
63void idea_set_encrypt_key(const unsigned char *key, IDEA_KEY_SCHEDULE *ks)
64	{
65	int i;
66	register IDEA_INT *kt,*kf,r0,r1,r2;
67
68	kt= &(ks->data[0][0]);
69	n2s(key,kt[0]); n2s(key,kt[1]); n2s(key,kt[2]); n2s(key,kt[3]);
70	n2s(key,kt[4]); n2s(key,kt[5]); n2s(key,kt[6]); n2s(key,kt[7]);
71
72	kf=kt;
73	kt+=8;
74	for (i=0; i<6; i++)
75		{
76		r2= kf[1];
77		r1= kf[2];
78		*(kt++)= ((r2<<9) | (r1>>7))&0xffff;
79		r0= kf[3];
80		*(kt++)= ((r1<<9) | (r0>>7))&0xffff;
81		r1= kf[4];
82		*(kt++)= ((r0<<9) | (r1>>7))&0xffff;
83		r0= kf[5];
84		*(kt++)= ((r1<<9) | (r0>>7))&0xffff;
85		r1= kf[6];
86		*(kt++)= ((r0<<9) | (r1>>7))&0xffff;
87		r0= kf[7];
88		*(kt++)= ((r1<<9) | (r0>>7))&0xffff;
89		r1= kf[0];
90		if (i >= 5) break;
91		*(kt++)= ((r0<<9) | (r1>>7))&0xffff;
92		*(kt++)= ((r1<<9) | (r2>>7))&0xffff;
93		kf+=8;
94		}
95	}
96
97void idea_set_decrypt_key(IDEA_KEY_SCHEDULE *ek, IDEA_KEY_SCHEDULE *dk)
98	{
99	int r;
100	register IDEA_INT *fp,*tp,t;
101
102	tp= &(dk->data[0][0]);
103	fp= &(ek->data[8][0]);
104	for (r=0; r<9; r++)
105		{
106		*(tp++)=inverse(fp[0]);
107		*(tp++)=((int)(0x10000L-fp[2])&0xffff);
108		*(tp++)=((int)(0x10000L-fp[1])&0xffff);
109		*(tp++)=inverse(fp[3]);
110		if (r == 8) break;
111		fp-=6;
112		*(tp++)=fp[4];
113		*(tp++)=fp[5];
114		}
115
116	tp= &(dk->data[0][0]);
117	t=tp[1];
118	tp[1]=tp[2];
119	tp[2]=t;
120
121	t=tp[49];
122	tp[49]=tp[50];
123	tp[50]=t;
124	}
125
126/* taken directly from the 'paper' I'll have a look at it later */
127static IDEA_INT inverse(unsigned int xin)
128	{
129	long n1,n2,q,r,b1,b2,t;
130
131	if (xin == 0)
132		b2=0;
133	else
134		{
135		n1=0x10001;
136		n2=xin;
137		b2=1;
138		b1=0;
139
140		do	{
141			r=(n1%n2);
142			q=(n1-r)/n2;
143			if (r == 0)
144				{ if (b2 < 0) b2=0x10001+b2; }
145			else
146				{
147				n1=n2;
148				n2=r;
149				t=b2;
150				b2=b1-q*b2;
151				b1=t;
152				}
153			} while (r != 0);
154		}
155	return((IDEA_INT)b2);
156	}
157