1/* crypto/des/cfb_enc.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59#include "des_locl.h"
60
61/* The input and output are loaded in multiples of 8 bits.
62 * What this means is that if you hame numbits=12 and length=2
63 * the first 12 bits will be retrieved from the first byte and half
64 * the second.  The second 12 bits will come from the 3rd and half the 4th
65 * byte.
66 */
67void des_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
68	     long length, des_key_schedule schedule, des_cblock *ivec, int enc)
69	{
70	register DES_LONG d0,d1,v0,v1,n=(numbits+7)/8;
71	register DES_LONG mask0,mask1;
72	register unsigned long l=length;
73	register int num=numbits;
74	DES_LONG ti[2];
75	unsigned char *iv;
76
77	if (num > 64) return;
78	if (num > 32)
79		{
80		mask0=0xffffffffL;
81		if (num == 64)
82			mask1=mask0;
83		else	mask1=(1L<<(num-32))-1;
84		}
85	else
86		{
87		if (num == 32)
88			mask0=0xffffffffL;
89		else	mask0=(1L<<num)-1;
90		mask1=0x00000000L;
91		}
92
93	iv = &(*ivec)[0];
94	c2l(iv,v0);
95	c2l(iv,v1);
96	if (enc)
97		{
98		while (l >= n)
99			{
100			l-=n;
101			ti[0]=v0;
102			ti[1]=v1;
103			des_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
104			c2ln(in,d0,d1,n);
105			in+=n;
106			d0=(d0^ti[0])&mask0;
107			d1=(d1^ti[1])&mask1;
108			l2cn(d0,d1,out,n);
109			out+=n;
110			/* 30-08-94 - eay - changed because l>>32 and
111			 * l<<32 are bad under gcc :-( */
112			if (num == 32)
113				{ v0=v1; v1=d0; }
114			else if (num == 64)
115				{ v0=d0; v1=d1; }
116			else if (num > 32) /* && num != 64 */
117				{
118				v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
119				v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
120				}
121			else /* num < 32 */
122				{
123				v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
124				v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
125				}
126			}
127		}
128	else
129		{
130		while (l >= n)
131			{
132			l-=n;
133			ti[0]=v0;
134			ti[1]=v1;
135			des_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
136			c2ln(in,d0,d1,n);
137			in+=n;
138			/* 30-08-94 - eay - changed because l>>32 and
139			 * l<<32 are bad under gcc :-( */
140			if (num == 32)
141				{ v0=v1; v1=d0; }
142			else if (num == 64)
143				{ v0=d0; v1=d1; }
144			else if (num > 32) /* && num != 64 */
145				{
146				v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
147				v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
148				}
149			else /* num < 32 */
150				{
151				v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
152				v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
153				}
154			d0=(d0^ti[0])&mask0;
155			d1=(d1^ti[1])&mask1;
156			l2cn(d0,d1,out,n);
157			out+=n;
158			}
159		}
160	iv = &(*ivec)[0];
161	l2c(v0,iv);
162	l2c(v1,iv);
163	v0=v1=d0=d1=ti[0]=ti[1]=0;
164	}
165
166