1/*
2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <openssl/idea.h>
11#include "idea_local.h"
12
13static IDEA_INT inverse(unsigned int xin);
14void IDEA_set_encrypt_key(const unsigned char *key, IDEA_KEY_SCHEDULE *ks)
15{
16 int i;
17 register IDEA_INT *kt, *kf, r0, r1, r2;
18
19 kt = &(ks->data[0][0]);
20 n2s(key, kt[0]);
21 n2s(key, kt[1]);
22 n2s(key, kt[2]);
23 n2s(key, kt[3]);
24 n2s(key, kt[4]);
25 n2s(key, kt[5]);
26 n2s(key, kt[6]);
27 n2s(key, kt[7]);
28
29 kf = kt;
30 kt += 8;
31 for (i = 0; i < 6; i++) {
32 r2 = kf[1];
33 r1 = kf[2];
34 *(kt++) = ((r2 << 9) | (r1 >> 7)) & 0xffff;
35 r0 = kf[3];
36 *(kt++) = ((r1 << 9) | (r0 >> 7)) & 0xffff;
37 r1 = kf[4];
38 *(kt++) = ((r0 << 9) | (r1 >> 7)) & 0xffff;
39 r0 = kf[5];
40 *(kt++) = ((r1 << 9) | (r0 >> 7)) & 0xffff;
41 r1 = kf[6];
42 *(kt++) = ((r0 << 9) | (r1 >> 7)) & 0xffff;
43 r0 = kf[7];
44 *(kt++) = ((r1 << 9) | (r0 >> 7)) & 0xffff;
45 r1 = kf[0];
46 if (i >= 5)
47 break;
48 *(kt++) = ((r0 << 9) | (r1 >> 7)) & 0xffff;
49 *(kt++) = ((r1 << 9) | (r2 >> 7)) & 0xffff;
50 kf += 8;
51 }
52}
53
54void IDEA_set_decrypt_key(IDEA_KEY_SCHEDULE *ek, IDEA_KEY_SCHEDULE *dk)
55{
56 int r;
57 register IDEA_INT *fp, *tp, t;
58
59 tp = &(dk->data[0][0]);
60 fp = &(ek->data[8][0]);
61 for (r = 0; r < 9; r++) {
62 *(tp++) = inverse(fp[0]);
63 *(tp++) = ((int)(0x10000L - fp[2]) & 0xffff);
64 *(tp++) = ((int)(0x10000L - fp[1]) & 0xffff);
65 *(tp++) = inverse(fp[3]);
66 if (r == 8)
67 break;
68 fp -= 6;
69 *(tp++) = fp[4];
70 *(tp++) = fp[5];
71 }
72
73 tp = &(dk->data[0][0]);
74 t = tp[1];
75 tp[1] = tp[2];
76 tp[2] = t;
77
78 t = tp[49];
79 tp[49] = tp[50];
80 tp[50] = t;
81}
82
83/* taken directly from the 'paper' I'll have a look at it later */
84static IDEA_INT inverse(unsigned int xin)
85{
86 long n1, n2, q, r, b1, b2, t;
87
88 if (xin == 0)
89 b2 = 0;
90 else {
91 n1 = 0x10001;
92 n2 = xin;
93 b2 = 1;
94 b1 = 0;
95
96 do {
97 r = (n1 % n2);
98 q = (n1 - r) / n2;
99 if (r == 0) {
100 if (b2 < 0)
101 b2 = 0x10001 + b2;
102 } else {
103 n1 = n2;
104 n2 = r;
105 t = b2;
106 b2 = b1 - q * b2;
107 b1 = t;
108 }
109 } while (r != 0);
110 }
111 return (IDEA_INT)b2;
112}
113