1 | /* |
2 | * Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved. |
3 | * |
4 | * Licensed under the Apache License 2.0 (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 |
8 | */ |
9 | |
10 | #include <string.h> |
11 | #include <openssl/crypto.h> |
12 | #include "crypto/modes.h" |
13 | |
14 | /* |
15 | * The input and output encrypted as though 128bit ofb 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; |
18 | */ |
19 | void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out, |
20 | size_t len, const void *key, |
21 | unsigned char ivec[16], int *num, block128_f block) |
22 | { |
23 | unsigned int n; |
24 | size_t l = 0; |
25 | |
26 | n = *num; |
27 | |
28 | #if !defined(OPENSSL_SMALL_FOOTPRINT) |
29 | if (16 % sizeof(size_t) == 0) { /* always true actually */ |
30 | do { |
31 | while (n && len) { |
32 | *(out++) = *(in++) ^ ivec[n]; |
33 | --len; |
34 | n = (n + 1) % 16; |
35 | } |
36 | # if defined(STRICT_ALIGNMENT) |
37 | if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != |
38 | 0) |
39 | break; |
40 | # endif |
41 | while (len >= 16) { |
42 | (*block) (ivec, ivec, key); |
43 | for (; n < 16; n += sizeof(size_t)) |
44 | *(size_t *)(out + n) = |
45 | *(size_t *)(in + n) ^ *(size_t *)(ivec + n); |
46 | len -= 16; |
47 | out += 16; |
48 | in += 16; |
49 | n = 0; |
50 | } |
51 | if (len) { |
52 | (*block) (ivec, ivec, key); |
53 | while (len--) { |
54 | out[n] = in[n] ^ ivec[n]; |
55 | ++n; |
56 | } |
57 | } |
58 | *num = n; |
59 | return; |
60 | } while (0); |
61 | } |
62 | /* the rest would be commonly eliminated by x86* compiler */ |
63 | #endif |
64 | while (l < len) { |
65 | if (n == 0) { |
66 | (*block) (ivec, ivec, key); |
67 | } |
68 | out[l] = in[l] ^ ivec[n]; |
69 | ++l; |
70 | n = (n + 1) % 16; |
71 | } |
72 | |
73 | *num = n; |
74 | } |
75 | |