2 * Copyright 2008-2020 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_local.h"
14 #if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
15 typedef size_t size_t_aX __attribute((__aligned__(1)));
17 typedef size_t size_t_aX;
21 * The input and output encrypted as though 128bit cfb mode is being used.
22 * The extra state information to record how much of the 128bit block we have
23 * used is contained in *num;
25 void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
26 size_t len, const void *key,
27 unsigned char ivec[16], int *num,
28 int enc, block128_f block)
36 #if !defined(OPENSSL_SMALL_FOOTPRINT)
37 if (16 % sizeof(size_t) == 0) { /* always true actually */
40 *(out++) = ivec[n] ^= *(in++);
44 # if defined(STRICT_ALIGNMENT)
45 if (((size_t)in | (size_t)out | (size_t)ivec) %
50 (*block) (ivec, ivec, key);
51 for (; n < 16; n += sizeof(size_t)) {
52 *(size_t_aX *)(out + n) =
53 *(size_t_aX *)(ivec + n)
54 ^= *(size_t_aX *)(in + n);
62 (*block) (ivec, ivec, key);
64 out[n] = ivec[n] ^= in[n];
72 /* the rest would be commonly eliminated by x86* compiler */
76 (*block) (ivec, ivec, key);
78 out[l] = ivec[n] ^= in[l];
84 #if !defined(OPENSSL_SMALL_FOOTPRINT)
85 if (16 % sizeof(size_t) == 0) { /* always true actually */
89 *(out++) = ivec[n] ^ (c = *(in++));
94 # if defined(STRICT_ALIGNMENT)
95 if (((size_t)in | (size_t)out | (size_t)ivec) %
100 (*block) (ivec, ivec, key);
101 for (; n < 16; n += sizeof(size_t)) {
102 size_t t = *(size_t_aX *)(in + n);
103 *(size_t_aX *)(out + n)
104 = *(size_t_aX *)(ivec + n) ^ t;
105 *(size_t_aX *)(ivec + n) = t;
113 (*block) (ivec, ivec, key);
116 out[n] = ivec[n] ^ (c = in[n]);
125 /* the rest would be commonly eliminated by x86* compiler */
130 (*block) (ivec, ivec, key);
132 out[l] = ivec[n] ^ (c = in[l]);
142 * This expects a single block of size nbits for both in and out. Note that
143 * it corrupts any extra bits in the last byte of out
145 static void cfbr_encrypt_block(const unsigned char *in, unsigned char *out,
146 int nbits, const void *key,
147 unsigned char ivec[16], int enc,
151 unsigned char ovec[16 * 2 + 1]; /* +1 because we dereference (but don't
152 * use) one byte off the end */
154 if (nbits <= 0 || nbits > 128)
157 /* fill in the first half of the new IV with the current IV */
158 memcpy(ovec, ivec, 16);
159 /* construct the new IV */
160 (*block) (ivec, ivec, key);
161 num = (nbits + 7) / 8;
162 if (enc) /* encrypt the input */
163 for (n = 0; n < num; ++n)
164 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
165 else /* decrypt the input */
166 for (n = 0; n < num; ++n)
167 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
168 /* shift ovec left... */
172 memcpy(ivec, ovec + num, 16);
174 for (n = 0; n < 16; ++n)
175 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
177 /* it is not necessary to cleanse ovec, since the IV is not secret */
180 /* N.B. This expects the input to be packed, MS bit first */
181 void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
182 size_t bits, const void *key,
183 unsigned char ivec[16], int *num,
184 int enc, block128_f block)
187 unsigned char c[1], d[1];
189 for (n = 0; n < bits; ++n) {
190 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
191 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
192 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
193 ((d[0] & 0x80) >> (unsigned int)(n % 8));
197 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
198 size_t length, const void *key,
199 unsigned char ivec[16], int *num,
200 int enc, block128_f block)
204 for (n = 0; n < length; ++n)
205 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);