1 /*
2 * Copyright 1995-2020 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 /*
11 * CAST low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include <openssl/cast.h>
17 #include "cast_local.h"
18
19 /*
20 * The input and output encrypted as though 64bit cfb mode is being used.
21 * The extra state information to record how much of the 64bit block we have
22 * used is contained in *num;
23 */
24
CAST_cfb64_encrypt(const unsigned char * in,unsigned char * out,long length,const CAST_KEY * schedule,unsigned char * ivec,int * num,int enc)25 void CAST_cfb64_encrypt(const unsigned char *in, unsigned char *out,
26 long length, const CAST_KEY *schedule,
27 unsigned char *ivec, int *num, int enc)
28 {
29 register CAST_LONG v0, v1, t;
30 register int n = *num;
31 register long l = length;
32 CAST_LONG ti[2];
33 unsigned char *iv, c, cc;
34
35 iv = ivec;
36 if (enc) {
37 while (l--) {
38 if (n == 0) {
39 n2l(iv, v0);
40 ti[0] = v0;
41 n2l(iv, v1);
42 ti[1] = v1;
43 CAST_encrypt((CAST_LONG *)ti, schedule);
44 iv = ivec;
45 t = ti[0];
46 l2n(t, iv);
47 t = ti[1];
48 l2n(t, iv);
49 iv = ivec;
50 }
51 c = *(in++) ^ iv[n];
52 *(out++) = c;
53 iv[n] = c;
54 n = (n + 1) & 0x07;
55 }
56 } else {
57 while (l--) {
58 if (n == 0) {
59 n2l(iv, v0);
60 ti[0] = v0;
61 n2l(iv, v1);
62 ti[1] = v1;
63 CAST_encrypt((CAST_LONG *)ti, schedule);
64 iv = ivec;
65 t = ti[0];
66 l2n(t, iv);
67 t = ti[1];
68 l2n(t, iv);
69 iv = ivec;
70 }
71 cc = *(in++);
72 c = iv[n];
73 iv[n] = cc;
74 *(out++) = c ^ cc;
75 n = (n + 1) & 0x07;
76 }
77 }
78 v0 = v1 = ti[0] = ti[1] = t = c = cc = 0;
79 *num = n;
80 }
81
