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 are loaded in multiples of 8 bits. What this means is
20 * that if you have numbits=12 and length=2 the first 12 bits will be
21 * retrieved from the first byte and half the second. The second 12 bits
22 * will come from the 3rd and half the 4th byte.
23 */
DES_ofb_encrypt(const unsigned char * in,unsigned char * out,int numbits,long length,DES_key_schedule * schedule,DES_cblock * ivec)24 void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
25 long length, DES_key_schedule *schedule,
26 DES_cblock *ivec)
27 {
28 register DES_LONG d0, d1, vv0, vv1, v0, v1, n = (numbits + 7) / 8;
29 register DES_LONG mask0, mask1;
30 register long l = length;
31 register int num = numbits;
32 DES_LONG ti[2];
33 unsigned char *iv;
34
35 if (num > 64)
36 return;
37 if (num > 32) {
38 mask0 = 0xffffffffL;
39 if (num >= 64)
40 mask1 = mask0;
41 else
42 mask1 = (1L << (num - 32)) - 1;
43 } else {
44 if (num == 32)
45 mask0 = 0xffffffffL;
46 else
47 mask0 = (1L << num) - 1;
48 mask1 = 0x00000000L;
49 }
50
51 iv = &(*ivec)[0];
52 c2l(iv, v0);
53 c2l(iv, v1);
54 ti[0] = v0;
55 ti[1] = v1;
56 while (l-- > 0) {
57 ti[0] = v0;
58 ti[1] = v1;
59 DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
60 vv0 = ti[0];
61 vv1 = ti[1];
62 c2ln(in, d0, d1, n);
63 in += n;
64 d0 = (d0 ^ vv0) & mask0;
65 d1 = (d1 ^ vv1) & mask1;
66 l2cn(d0, d1, out, n);
67 out += n;
68
69 if (num == 32) {
70 v0 = v1;
71 v1 = vv0;
72 } else if (num == 64) {
73 v0 = vv0;
74 v1 = vv1;
75 } else if (num > 32) { /* && num != 64 */
76 v0 = ((v1 >> (num - 32)) | (vv0 << (64 - num))) & 0xffffffffL;
77 v1 = ((vv0 >> (num - 32)) | (vv1 << (64 - num))) & 0xffffffffL;
78 } else { /* num < 32 */
79
80 v0 = ((v0 >> num) | (v1 << (32 - num))) & 0xffffffffL;
81 v1 = ((v1 >> num) | (vv0 << (32 - num))) & 0xffffffffL;
82 }
83 }
84 iv = &(*ivec)[0];
85 l2c(v0, iv);
86 l2c(v1, iv);
87 v0 = v1 = d0 = d1 = ti[0] = ti[1] = vv0 = vv1 = 0;
88 }
89
