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 | |
13 | static IDEA_INT inverse(unsigned int xin); |
14 | void 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 | |
54 | void 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 */ |
84 | static 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 | |