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/cast.h> |
11 | #include "cast_local.h" |
12 | |
13 | /* |
14 | * The input and output encrypted as though 64bit cfb mode is being used. |
15 | * The extra state information to record how much of the 64bit block we have |
16 | * used is contained in *num; |
17 | */ |
18 | |
19 | void CAST_cfb64_encrypt(const unsigned char *in, unsigned char *out, |
20 | long length, const CAST_KEY *schedule, |
21 | unsigned char *ivec, int *num, int enc) |
22 | { |
23 | register CAST_LONG v0, v1, t; |
24 | register int n = *num; |
25 | register long l = length; |
26 | CAST_LONG ti[2]; |
27 | unsigned char *iv, c, cc; |
28 | |
29 | iv = ivec; |
30 | if (enc) { |
31 | while (l--) { |
32 | if (n == 0) { |
33 | n2l(iv, v0); |
34 | ti[0] = v0; |
35 | n2l(iv, v1); |
36 | ti[1] = v1; |
37 | CAST_encrypt((CAST_LONG *)ti, schedule); |
38 | iv = ivec; |
39 | t = ti[0]; |
40 | l2n(t, iv); |
41 | t = ti[1]; |
42 | l2n(t, iv); |
43 | iv = ivec; |
44 | } |
45 | c = *(in++) ^ iv[n]; |
46 | *(out++) = c; |
47 | iv[n] = c; |
48 | n = (n + 1) & 0x07; |
49 | } |
50 | } else { |
51 | while (l--) { |
52 | if (n == 0) { |
53 | n2l(iv, v0); |
54 | ti[0] = v0; |
55 | n2l(iv, v1); |
56 | ti[1] = v1; |
57 | CAST_encrypt((CAST_LONG *)ti, schedule); |
58 | iv = ivec; |
59 | t = ti[0]; |
60 | l2n(t, iv); |
61 | t = ti[1]; |
62 | l2n(t, iv); |
63 | iv = ivec; |
64 | } |
65 | cc = *(in++); |
66 | c = iv[n]; |
67 | iv[n] = cc; |
68 | *(out++) = c ^ cc; |
69 | n = (n + 1) & 0x07; |
70 | } |
71 | } |
72 | v0 = v1 = ti[0] = ti[1] = t = c = cc = 0; |
73 | *num = n; |
74 | } |
75 | |