text: #ifndef _FS_CEPH_CRYPTO_H
  #define _FS_CEPH_CRYPTO_H
  
  #include <linux/ceph/types.h>
  #include <linux/ceph/buffer.h>
  
  /*
   * cryptographic secret
   */
  struct ceph_crypto_key {
  	int type;
  	struct ceph_timespec created;
  	int len;
  	void *key;
  };
  
  static inline void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
  {
  	if (key)
  		kfree(key->key);
  }
  
  extern int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
  				 const struct ceph_crypto_key *src);
  extern int ceph_crypto_key_encode(struct ceph_crypto_key *key,
  				  void **p, void *end);
  extern int ceph_crypto_key_decode(struct ceph_crypto_key *key,
  				  void **p, void *end);
  extern int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *in);
  
  /* crypto.c */
  extern int ceph_decrypt(struct ceph_crypto_key *secret,
  			void *dst, size_t *dst_len,
  			const void *src, size_t src_len);
  extern int ceph_encrypt(struct ceph_crypto_key *secret,
  			void *dst, size_t *dst_len,
  			const void *src, size_t src_len);
  extern int ceph_decrypt2(struct ceph_crypto_key *secret,
  			void *dst1, size_t *dst1_len,
  			void *dst2, size_t *dst2_len,
  			const void *src, size_t src_len);
  extern int ceph_encrypt2(struct ceph_crypto_key *secret,
  			 void *dst, size_t *dst_len,
  			 const void *src1, size_t src1_len,
  			 const void *src2, size_t src2_len);
  extern int ceph_crypto_init(void);
  extern void ceph_crypto_shutdown(void);
  
  /* armor.c */
  extern int ceph_armor(char *dst, const char *src, const char *end);
  extern int ceph_unarmor(char *dst, const char *src, const char *end);
  
  #endif
  