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d02b48c6 | 1 | /* crypto/idea/i_skey.c */ |
58964a49 | 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
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 "idea.h" | |
60 | #include "idea_lcl.h" | |
61 | ||
62 | #ifndef NOPROTO | |
63 | static IDEA_INT inverse(unsigned int xin); | |
64 | #else | |
65 | static IDEA_INT inverse(); | |
66 | #endif | |
67 | ||
68 | void idea_set_encrypt_key(key, ks) | |
69 | unsigned char *key; | |
70 | IDEA_KEY_SCHEDULE *ks; | |
71 | { | |
72 | int i; | |
73 | register IDEA_INT *kt,*kf,r0,r1,r2; | |
74 | ||
75 | kt= &(ks->data[0][0]); | |
76 | n2s(key,kt[0]); n2s(key,kt[1]); n2s(key,kt[2]); n2s(key,kt[3]); | |
77 | n2s(key,kt[4]); n2s(key,kt[5]); n2s(key,kt[6]); n2s(key,kt[7]); | |
78 | ||
79 | kf=kt; | |
80 | kt+=8; | |
81 | for (i=0; i<6; i++) | |
82 | { | |
83 | r2= kf[1]; | |
84 | r1= kf[2]; | |
85 | *(kt++)= ((r2<<9) | (r1>>7))&0xffff; | |
86 | r0= kf[3]; | |
87 | *(kt++)= ((r1<<9) | (r0>>7))&0xffff; | |
88 | r1= kf[4]; | |
89 | *(kt++)= ((r0<<9) | (r1>>7))&0xffff; | |
90 | r0= kf[5]; | |
91 | *(kt++)= ((r1<<9) | (r0>>7))&0xffff; | |
92 | r1= kf[6]; | |
93 | *(kt++)= ((r0<<9) | (r1>>7))&0xffff; | |
94 | r0= kf[7]; | |
95 | *(kt++)= ((r1<<9) | (r0>>7))&0xffff; | |
96 | r1= kf[0]; | |
97 | if (i >= 5) break; | |
98 | *(kt++)= ((r0<<9) | (r1>>7))&0xffff; | |
99 | *(kt++)= ((r1<<9) | (r2>>7))&0xffff; | |
100 | kf+=8; | |
101 | } | |
102 | } | |
103 | ||
104 | void idea_set_decrypt_key(ek, dk) | |
105 | IDEA_KEY_SCHEDULE *ek; | |
106 | IDEA_KEY_SCHEDULE *dk; | |
107 | { | |
108 | int r; | |
109 | register IDEA_INT *fp,*tp,t; | |
110 | ||
111 | tp= &(dk->data[0][0]); | |
112 | fp= &(ek->data[8][0]); | |
113 | for (r=0; r<9; r++) | |
114 | { | |
115 | *(tp++)=inverse(fp[0]); | |
116 | *(tp++)=((int)(0x10000L-fp[2])&0xffff); | |
117 | *(tp++)=((int)(0x10000L-fp[1])&0xffff); | |
118 | *(tp++)=inverse(fp[3]); | |
119 | if (r == 8) break; | |
120 | fp-=6; | |
121 | *(tp++)=fp[4]; | |
122 | *(tp++)=fp[5]; | |
123 | } | |
124 | ||
125 | tp= &(dk->data[0][0]); | |
126 | t=tp[1]; | |
127 | tp[1]=tp[2]; | |
128 | tp[2]=t; | |
129 | ||
130 | t=tp[49]; | |
131 | tp[49]=tp[50]; | |
132 | tp[50]=t; | |
133 | } | |
134 | ||
135 | /* taken directly from the 'paper' I'll have a look at it later */ | |
136 | static IDEA_INT inverse(xin) | |
137 | unsigned int xin; | |
138 | { | |
139 | long n1,n2,q,r,b1,b2,t; | |
140 | ||
141 | if (xin == 0) | |
142 | b2=0; | |
143 | else | |
144 | { | |
145 | n1=0x10001; | |
146 | n2=xin; | |
147 | b2=1; | |
148 | b1=0; | |
149 | ||
150 | do { | |
151 | r=(n1%n2); | |
152 | q=(n1-r)/n2; | |
153 | if (r == 0) | |
154 | { if (b2 < 0) b2=0x10001+b2; } | |
155 | else | |
156 | { | |
157 | n1=n2; | |
158 | n2=r; | |
159 | t=b2; | |
160 | b2=b1-q*b2; | |
161 | b1=t; | |
162 | } | |
163 | } while (r != 0); | |
164 | } | |
165 | return((IDEA_INT)b2); | |
166 | } |