1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Common values for the ChaCha20 algorithm
4  */
5 
6 #ifndef _CRYPTO_CHACHA20_H
7 #define _CRYPTO_CHACHA20_H
8 
9 #include <crypto/skcipher.h>
10 #include <linux/types.h>
11 #include <linux/crypto.h>
12 
13 #define CHACHA20_IV_SIZE	16
14 #define CHACHA20_KEY_SIZE	32
15 #define CHACHA20_BLOCK_SIZE	64
16 
17 struct chacha20_ctx {
18 	u32 key[8];
19 };
20 
21 void chacha20_block(u32 *state, u8 *stream);
22 void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv);
23 int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
24 			   unsigned int keysize);
25 int crypto_chacha20_crypt(struct skcipher_request *req);
26 
27 enum chacha_constants { /* expand 32-byte k */
28 	CHACHA_CONSTANT_EXPA = 0x61707865U,
29 	CHACHA_CONSTANT_ND_3 = 0x3320646eU,
30 	CHACHA_CONSTANT_2_BY = 0x79622d32U,
31 	CHACHA_CONSTANT_TE_K = 0x6b206574U
32 };
33 
chacha_init_consts(u32 * state)34 static inline void chacha_init_consts(u32 *state)
35 {
36 	state[0]  = CHACHA_CONSTANT_EXPA;
37 	state[1]  = CHACHA_CONSTANT_ND_3;
38 	state[2]  = CHACHA_CONSTANT_2_BY;
39 	state[3]  = CHACHA_CONSTANT_TE_K;
40 }
41 
42 #endif
43