1. 根目录:
2. include
3. crypto
4. null.h

/* Values for NULL algorithms */

#ifndef _CRYPTO_NULL_H
#define _CRYPTO_NULL_H

#define NULL_KEY_SIZE		0
#define NULL_BLOCK_SIZE		1
#define NULL_DIGEST_SIZE	0
#define NULL_IV_SIZE		0

struct crypto_blkcipher *crypto_get_default_null_skcipher(void);
void crypto_put_default_null_skcipher(void);

#endif