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 * DES low level APIs are deprecated for public use, but still ok for internal
12 * use.
13 */
14 #include "internal/deprecated.h"
15
16 #include "des_local.h"
17
18 /*
19 * The input and output encrypted as though 64bit cfb mode is being used.
20 * The extra state information to record how much of the 64bit block we have
21 * used is contained in *num;
22 */
23
DES_cfb64_encrypt(const unsigned char * in,unsigned char * out,long length,DES_key_schedule * schedule,DES_cblock * ivec,int * num,int enc)24 void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out,
25 long length, DES_key_schedule *schedule,
26 DES_cblock *ivec, int *num, int enc)
27 {
28 register DES_LONG v0, v1;
29 register long l = length;
30 register int n = *num;
31 DES_LONG ti[2];
32 unsigned char *iv, c, cc;
33
34 iv = &(*ivec)[0];
35 if (enc) {
36 while (l--) {
37 if (n == 0) {
38 c2l(iv, v0);
39 ti[0] = v0;
40 c2l(iv, v1);
41 ti[1] = v1;
42 DES_encrypt1(ti, schedule, DES_ENCRYPT);
43 iv = &(*ivec)[0];
44 v0 = ti[0];
45 l2c(v0, iv);
46 v0 = ti[1];
47 l2c(v0, iv);
48 iv = &(*ivec)[0];
49 }
50 c = *(in++) ^ iv[n];
51 *(out++) = c;
52 iv[n] = c;
53 n = (n + 1) & 0x07;
54 }
55 } else {
56 while (l--) {
57 if (n == 0) {
58 c2l(iv, v0);
59 ti[0] = v0;
60 c2l(iv, v1);
61 ti[1] = v1;
62 DES_encrypt1(ti, schedule, DES_ENCRYPT);
63 iv = &(*ivec)[0];
64 v0 = ti[0];
65 l2c(v0, iv);
66 v0 = ti[1];
67 l2c(v0, iv);
68 iv = &(*ivec)[0];
69 }
70 cc = *(in++);
71 c = iv[n];
72 iv[n] = cc;
73 *(out++) = c ^ cc;
74 n = (n + 1) & 0x07;
75 }
76 }
77 v0 = v1 = ti[0] = ti[1] = c = cc = 0;
78 *num = n;
79 }
80