2 * Copyright 2008-2016 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
10 #include <openssl/crypto.h>
11 #include "modes_lcl.h"
15 * The input and output encrypted as though 128bit cfb mode is being used.
16 * The extra state information to record how much of the 128bit block we have
17 * used is contained in *num;
19 void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
20 size_t len, const void *key,
21 unsigned char ivec[16], int *num,
22 int enc, block128_f block)
30 #if !defined(OPENSSL_SMALL_FOOTPRINT)
31 if (16 % sizeof(size_t) == 0) { /* always true actually */
34 *(out++) = ivec[n] ^= *(in++);
38 # if defined(STRICT_ALIGNMENT)
39 if (((size_t)in | (size_t)out | (size_t)ivec) %
44 (*block) (ivec, ivec, key);
45 for (; n < 16; n += sizeof(size_t)) {
46 *(size_t *)(out + n) =
47 *(size_t *)(ivec + n) ^= *(size_t *)(in + n);
55 (*block) (ivec, ivec, key);
57 out[n] = ivec[n] ^= in[n];
65 /* the rest would be commonly eliminated by x86* compiler */
69 (*block) (ivec, ivec, key);
71 out[l] = ivec[n] ^= in[l];
77 #if !defined(OPENSSL_SMALL_FOOTPRINT)
78 if (16 % sizeof(size_t) == 0) { /* always true actually */
82 *(out++) = ivec[n] ^ (c = *(in++));
87 # if defined(STRICT_ALIGNMENT)
88 if (((size_t)in | (size_t)out | (size_t)ivec) %
93 (*block) (ivec, ivec, key);
94 for (; n < 16; n += sizeof(size_t)) {
95 size_t t = *(size_t *)(in + n);
96 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t;
97 *(size_t *)(ivec + n) = t;
105 (*block) (ivec, ivec, key);
108 out[n] = ivec[n] ^ (c = in[n]);
117 /* the rest would be commonly eliminated by x86* compiler */
122 (*block) (ivec, ivec, key);
124 out[l] = ivec[n] ^ (c = in[l]);
134 * This expects a single block of size nbits for both in and out. Note that
135 * it corrupts any extra bits in the last byte of out
137 static void cfbr_encrypt_block(const unsigned char *in, unsigned char *out,
138 int nbits, const void *key,
139 unsigned char ivec[16], int enc,
143 unsigned char ovec[16 * 2 + 1]; /* +1 because we dereference (but don't
144 * use) one byte off the end */
146 if (nbits <= 0 || nbits > 128)
149 /* fill in the first half of the new IV with the current IV */
150 memcpy(ovec, ivec, 16);
151 /* construct the new IV */
152 (*block) (ivec, ivec, key);
153 num = (nbits + 7) / 8;
154 if (enc) /* encrypt the input */
155 for (n = 0; n < num; ++n)
156 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
157 else /* decrypt the input */
158 for (n = 0; n < num; ++n)
159 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
160 /* shift ovec left... */
164 memcpy(ivec, ovec + num, 16);
166 for (n = 0; n < 16; ++n)
167 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
169 /* it is not necessary to cleanse ovec, since the IV is not secret */
172 /* N.B. This expects the input to be packed, MS bit first */
173 void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
174 size_t bits, const void *key,
175 unsigned char ivec[16], int *num,
176 int enc, block128_f block)
179 unsigned char c[1], d[1];
181 for (n = 0; n < bits; ++n) {
182 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
183 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
184 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
185 ((d[0] & 0x80) >> (unsigned int)(n % 8));
189 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
190 size_t length, const void *key,
191 unsigned char ivec[16], int *num,
192 int enc, block128_f block)
196 for (n = 0; n < length; ++n)
197 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);