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
19void 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