1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Common values and helper functions for the ChaCha and XChaCha stream ciphers.
*
* XChaCha extends ChaCha's nonce to 192 bits, while provably retaining ChaCha's
* security. Here they share the same key size, tfm context, and setkey
* function; only their IV size and encrypt/decrypt function differ.
*
* The ChaCha paper specifies 20, 12, and 8-round variants. In general, it is
* recommended to use the 20-round variant ChaCha20. However, the other
* variants can be needed in some performance-sensitive scenarios. The generic
* ChaCha code currently allows only the 20 and 12-round variants.
*/
#ifndef _CRYPTO_CHACHA_H
#define _CRYPTO_CHACHA_H
#include <crypto/skcipher.h>
#include <linux/types.h>
#include <linux/crypto.h>
/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
#define CHACHA_IV_SIZE 16
#define CHACHA_KEY_SIZE 32
#define CHACHA_BLOCK_SIZE 64
#define CHACHAPOLY_IV_SIZE 12
/* 192-bit nonce, then 64-bit stream position */
#define XCHACHA_IV_SIZE 32
struct chacha_ctx {
u32 key[8];
int nrounds;
};
void chacha_block(u32 *state, u8 *stream, int nrounds);
static inline void chacha20_block(u32 *state, u8 *stream)
{
chacha_block(state, stream, 20);
}
void hchacha_block(const u32 *in, u32 *out, int nrounds);
void crypto_chacha_init(u32 *state, struct chacha_ctx *ctx, u8 *iv);
int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize);
int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize);
int crypto_chacha_crypt(struct skcipher_request *req);
int crypto_xchacha_crypt(struct skcipher_request *req);
#endif /* _CRYPTO_CHACHA_H */
|
