1/* ====================================================================
2 * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in
13 *    the documentation and/or other materials provided with the
14 *    distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 *    software must display the following acknowledgment:
18 *    "This product includes software developed by the OpenSSL Project
19 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 *    endorse or promote products derived from this software without
23 *    prior written permission. For written permission, please contact
24 *    openssl-core@openssl.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 *    nor may "OpenSSL" appear in their names without prior written
28 *    permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 *    acknowledgment:
32 *    "This product includes software developed by the OpenSSL Project
33 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 */
50
51#include <openssl/crypto.h>
52#include "modes_lcl.h"
53#include <string.h>
54
55#ifndef MODES_DEBUG
56# ifndef NDEBUG
57#  define NDEBUG
58# endif
59#endif
60#include <assert.h>
61
62/* The input and output encrypted as though 128bit ofb mode is being
63 * used.  The extra state information to record how much of the
64 * 128bit block we have used is contained in *num;
65 */
66void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
67			size_t len, const void *key,
68			unsigned char ivec[16], int *num,
69			block128_f block)
70{
71	unsigned int n;
72	size_t l=0;
73
74	assert(in && out && key && ivec && num);
75
76	n = *num;
77
78#if !defined(OPENSSL_SMALL_FOOTPRINT)
79	if (16%sizeof(size_t) == 0) do { /* always true actually */
80		while (n && len) {
81			*(out++) = *(in++) ^ ivec[n];
82			--len;
83			n = (n+1) % 16;
84		}
85#if defined(STRICT_ALIGNMENT)
86		if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
87			break;
88#endif
89		while (len>=16) {
90			(*block)(ivec, ivec, key);
91			for (; n<16; n+=sizeof(size_t))
92				*(size_t*)(out+n) =
93				*(size_t*)(in+n) ^ *(size_t*)(ivec+n);
94			len -= 16;
95			out += 16;
96			in  += 16;
97			n = 0;
98		}
99		if (len) {
100			(*block)(ivec, ivec, key);
101			while (len--) {
102				out[n] = in[n] ^ ivec[n];
103				++n;
104			}
105		}
106		*num = n;
107		return;
108	} while(0);
109	/* the rest would be commonly eliminated by x86* compiler */
110#endif
111	while (l<len) {
112		if (n==0) {
113			(*block)(ivec, ivec, key);
114		}
115		out[l] = in[l] ^ ivec[n];
116		++l;
117		n = (n+1) % 16;
118	}
119
120	*num=n;
121}
122