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git.ipfire.org Git - thirdparty/openssl.git/blob - crypto/des/cfb_enc.c
2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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
15 * The input and output are loaded in multiples of 8 bits. What this means is
16 * that if you hame numbits=12 and length=2 the first 12 bits will be
17 * retrieved from the first byte and half the second. The second 12 bits
18 * will come from the 3rd and half the 4th byte.
21 * Until Aug 1 2003 this function did not correctly implement CFB-r, so it
22 * will not be compatible with any encryption prior to that date. Ben.
24 void DES_cfb_encrypt(const unsigned char *in
, unsigned char *out
, int numbits
,
25 long length
, DES_key_schedule
*schedule
,
26 DES_cblock
*ivec
, int enc
)
28 register DES_LONG d0
, d1
, v0
, v1
;
29 register unsigned long l
= length
;
30 register int num
= numbits
/ 8, n
= (numbits
+ 7) / 8, i
, rem
=
35 unsigned char ovec
[16];
38 unsigned char *ovec
= (unsigned char *)sh
;
40 /* I kind of count that compiler optimizes away this assertioni, */
41 assert(sizeof(sh
[0]) == 4); /* as this holds true for all, */
42 /* but 16-bit platforms... */
46 if (numbits
<= 0 || numbits
> 64)
52 while (l
>= (unsigned long)n
) {
56 DES_encrypt1((DES_LONG
*)ti
, schedule
, DES_ENCRYPT
);
64 * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
70 } else if (numbits
== 64) {
81 sh
[0] = v0
, sh
[1] = v1
, sh
[2] = d0
, sh
[3] = d1
;
84 memmove(ovec
, ovec
+ num
, 8);
86 for (i
= 0; i
< 8; ++i
)
87 ovec
[i
] = ovec
[i
+ num
] << rem
|
88 ovec
[i
+ num
+ 1] >> (8 - rem
);
90 v0
= sh
[0], v1
= sh
[1];
99 while (l
>= (unsigned long)n
) {
103 DES_encrypt1((DES_LONG
*)ti
, schedule
, DES_ENCRYPT
);
107 * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
113 } else if (numbits
== 64) {
124 sh
[0] = v0
, sh
[1] = v1
, sh
[2] = d0
, sh
[3] = d1
;
127 memmove(ovec
, ovec
+ num
, 8);
129 for (i
= 0; i
< 8; ++i
)
130 ovec
[i
] = ovec
[i
+ num
] << rem
|
131 ovec
[i
+ num
+ 1] >> (8 - rem
);
133 v0
= sh
[0], v1
= sh
[1];
142 l2cn(d0
, d1
, out
, n
);
149 v0
= v1
= d0
= d1
= ti
[0] = ti
[1] = 0;