xref: /openssl/crypto/des/ofb64enc.c (revision 33388b44)
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 ofb 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  */
DES_ofb64_encrypt(register const unsigned char * in,register unsigned char * out,long length,DES_key_schedule * schedule,DES_cblock * ivec,int * num)23 void DES_ofb64_encrypt(register const unsigned char *in,
24                        register unsigned char *out, long length,
25                        DES_key_schedule *schedule, DES_cblock *ivec, int *num)
26 {
27     register DES_LONG v0, v1, t;
28     register int n = *num;
29     register long l = length;
30     DES_cblock d;
31     register unsigned char *dp;
32     DES_LONG ti[2];
33     unsigned char *iv;
34     int save = 0;
35 
36     iv = &(*ivec)[0];
37     c2l(iv, v0);
38     c2l(iv, v1);
39     ti[0] = v0;
40     ti[1] = v1;
41     dp = d;
42     l2c(v0, dp);
43     l2c(v1, dp);
44     while (l--) {
45         if (n == 0) {
46             DES_encrypt1(ti, schedule, DES_ENCRYPT);
47             dp = d;
48             t = ti[0];
49             l2c(t, dp);
50             t = ti[1];
51             l2c(t, dp);
52             save++;
53         }
54         *(out++) = *(in++) ^ d[n];
55         n = (n + 1) & 0x07;
56     }
57     if (save) {
58         v0 = ti[0];
59         v1 = ti[1];
60         iv = &(*ivec)[0];
61         l2c(v0, iv);
62         l2c(v1, iv);
63     }
64     t = v0 = v1 = ti[0] = ti[1] = 0;
65     *num = n;
66 }
67