1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10
11 /**
12 @file ocb3_int_xor_blocks.c
13 OCB implementation, INTERNAL ONLY helper, by Karel Miko
14 */
15 #include "tomcrypt_private.h"
16
17 #ifdef LTC_OCB3_MODE
18
19 /**
20 Compute xor for two blocks of bytes 'out = block_a XOR block_b' (internal function)
21 @param out The block of bytes (output)
22 @param block_a The block of bytes (input)
23 @param block_b The block of bytes (input)
24 @param block_len The size of block_a, block_b, out
25 */
ocb3_int_xor_blocks(unsigned char * out,const unsigned char * block_a,const unsigned char * block_b,unsigned long block_len)26 void ocb3_int_xor_blocks(unsigned char *out, const unsigned char *block_a, const unsigned char *block_b, unsigned long block_len)
27 {
28 int x;
29 if (out == block_a) {
30 for (x = 0; x < (int)block_len; x++) out[x] ^= block_b[x];
31 }
32 else {
33 for (x = 0; x < (int)block_len; x++) out[x] = block_a[x] ^ block_b[x];
34 }
35 }
36
37 #endif
38
39 /* ref: $Format:%D$ */
40 /* git commit: $Format:%H$ */
41 /* commit time: $Format:%ai$ */
42