xref: /optee_os/core/lib/libtomcrypt/des2_key.h (revision 96098f011f7cc334d2c9eb694e1cc45ded4f64cf)
1*96098f01SJens Wiklander /* SPDX-License-Identifier: BSD-2-Clause */
2*96098f01SJens Wiklander /*
3*96098f01SJens Wiklander  * Copyright (c) 2014-2019, Linaro Limited
4*96098f01SJens Wiklander  */
5*96098f01SJens Wiklander 
get_des2_key(const uint8_t ** key,size_t * key_len,uint8_t * tmp)6*96098f01SJens Wiklander static inline void get_des2_key(const uint8_t **key, size_t *key_len,
7*96098f01SJens Wiklander 				uint8_t *tmp)
8*96098f01SJens Wiklander {
9*96098f01SJens Wiklander 	if (*key_len == 16) {
10*96098f01SJens Wiklander 		/*
11*96098f01SJens Wiklander 		 * This corresponds to a 2DES key. The 2DES encryption
12*96098f01SJens Wiklander 		 * algorithm is similar to 3DES. Both perform and
13*96098f01SJens Wiklander 		 * encryption step, then a decryption step, followed
14*96098f01SJens Wiklander 		 * by another encryption step (EDE). However 2DES uses
15*96098f01SJens Wiklander 		 * the same key for both of the encryption (E) steps.
16*96098f01SJens Wiklander 		 */
17*96098f01SJens Wiklander 		memcpy(tmp, *key, 16);
18*96098f01SJens Wiklander 		memcpy(tmp + 16, *key, 8);
19*96098f01SJens Wiklander 		*key = tmp;
20*96098f01SJens Wiklander 		*key_len = 24;
21*96098f01SJens Wiklander 	}
22*96098f01SJens Wiklander }
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