openssl/crypto/modes/ofb128.c
Shane Lontis 459b15d451 Add Common shared code needed to move aes ciphers to providers
Custom aes ciphers will be placed into multiple new files
(instead of the monolithic setup used in the e_aes.c legacy code)
so it makes sense to have a header for the platform specific
code that needs to be shared between files.
modes_lcl.h has also moved to modes_int.h to allow sharing with the
provider source.
Code that will be common to AEAD ciphers has also been added. These
will be used by seperate PR's for GCM, CCM & OCB.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9301)
2019-07-16 09:46:14 +10:00

74 lines
2.1 KiB
C

/*
* Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <string.h>
#include <openssl/crypto.h>
#include "internal/modes_int.h"
/*
* The input and output encrypted as though 128bit ofb mode is being used.
* The extra state information to record how much of the 128bit block we have
* used is contained in *num;
*/
void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
size_t len, const void *key,
unsigned char ivec[16], int *num, block128_f block)
{
unsigned int n;
size_t l = 0;
n = *num;
#if !defined(OPENSSL_SMALL_FOOTPRINT)
if (16 % sizeof(size_t) == 0) { /* always true actually */
do {
while (n && len) {
*(out++) = *(in++) ^ ivec[n];
--len;
n = (n + 1) % 16;
}
# if defined(STRICT_ALIGNMENT)
if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) !=
0)
break;
# endif
while (len >= 16) {
(*block) (ivec, ivec, key);
for (; n < 16; n += sizeof(size_t))
*(size_t *)(out + n) =
*(size_t *)(in + n) ^ *(size_t *)(ivec + n);
len -= 16;
out += 16;
in += 16;
n = 0;
}
if (len) {
(*block) (ivec, ivec, key);
while (len--) {
out[n] = in[n] ^ ivec[n];
++n;
}
}
*num = n;
return;
} while (0);
}
/* the rest would be commonly eliminated by x86* compiler */
#endif
while (l < len) {
if (n == 0) {
(*block) (ivec, ivec, key);
}
out[l] = in[l] ^ ivec[n];
++l;
n = (n + 1) % 16;
}
*num = n;
}