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d2e9e320 RS |
1 | /* |
2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. | |
0f113f3e | 3 | * |
2d48d5dd | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
d2e9e320 RS |
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 | |
d02b48c6 RE |
8 | */ |
9 | ||
10 | #include "des_locl.h" | |
11 | ||
0f113f3e MC |
12 | /* |
13 | * The input and output are loaded in multiples of 8 bits. What this means is | |
0d4fb843 | 14 | * that if you have numbits=12 and length=2 the first 12 bits will be |
0f113f3e MC |
15 | * retrieved from the first byte and half the second. The second 12 bits |
16 | * will come from the 3rd and half the 4th byte. | |
d02b48c6 | 17 | */ |
c2e4f17c | 18 | void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits, |
0f113f3e MC |
19 | long length, DES_key_schedule *schedule, |
20 | DES_cblock *ivec) | |
21 | { | |
22 | register DES_LONG d0, d1, vv0, vv1, v0, v1, n = (numbits + 7) / 8; | |
23 | register DES_LONG mask0, mask1; | |
24 | register long l = length; | |
25 | register int num = numbits; | |
26 | DES_LONG ti[2]; | |
27 | unsigned char *iv; | |
d02b48c6 | 28 | |
0f113f3e MC |
29 | if (num > 64) |
30 | return; | |
31 | if (num > 32) { | |
32 | mask0 = 0xffffffffL; | |
33 | if (num >= 64) | |
34 | mask1 = mask0; | |
35 | else | |
36 | mask1 = (1L << (num - 32)) - 1; | |
37 | } else { | |
38 | if (num == 32) | |
39 | mask0 = 0xffffffffL; | |
40 | else | |
41 | mask0 = (1L << num) - 1; | |
42 | mask1 = 0x00000000L; | |
43 | } | |
d02b48c6 | 44 | |
0f113f3e MC |
45 | iv = &(*ivec)[0]; |
46 | c2l(iv, v0); | |
47 | c2l(iv, v1); | |
48 | ti[0] = v0; | |
49 | ti[1] = v1; | |
50 | while (l-- > 0) { | |
51 | ti[0] = v0; | |
52 | ti[1] = v1; | |
53 | DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); | |
54 | vv0 = ti[0]; | |
55 | vv1 = ti[1]; | |
56 | c2ln(in, d0, d1, n); | |
57 | in += n; | |
58 | d0 = (d0 ^ vv0) & mask0; | |
59 | d1 = (d1 ^ vv1) & mask1; | |
60 | l2cn(d0, d1, out, n); | |
61 | out += n; | |
58964a49 | 62 | |
0f113f3e MC |
63 | if (num == 32) { |
64 | v0 = v1; | |
65 | v1 = vv0; | |
66 | } else if (num == 64) { | |
67 | v0 = vv0; | |
68 | v1 = vv1; | |
69 | } else if (num > 32) { /* && num != 64 */ | |
70 | v0 = ((v1 >> (num - 32)) | (vv0 << (64 - num))) & 0xffffffffL; | |
71 | v1 = ((vv0 >> (num - 32)) | (vv1 << (64 - num))) & 0xffffffffL; | |
72 | } else { /* num < 32 */ | |
d02b48c6 | 73 | |
0f113f3e MC |
74 | v0 = ((v0 >> num) | (v1 << (32 - num))) & 0xffffffffL; |
75 | v1 = ((v1 >> num) | (vv0 << (32 - num))) & 0xffffffffL; | |
76 | } | |
77 | } | |
78 | iv = &(*ivec)[0]; | |
79 | l2c(v0, iv); | |
80 | l2c(v1, iv); | |
81 | v0 = v1 = d0 = d1 = ti[0] = ti[1] = vv0 = vv1 = 0; | |
82 | } |