1/*
2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (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