include/openssl/aead.h - boringssl - Git at Google

 /* Copyright (c) 2014, Google Inc.
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

 #ifndef OPENSSL_HEADER_AEAD_H
 #define OPENSSL_HEADER_AEAD_H

 #include <openssl/base.h>

 #if defined(__cplusplus)
 extern "C" {
 #endif


 /* Authenticated Encryption with Additional Data.
  *
  * AEAD couples confidentiality and integrity in a single primtive. AEAD
  * algorithms take a key and then can seal and open individual messages. Each
  * message has a unique, per-message nonce and, optionally, additional data
  * which is authenticated but not included in the ciphertext.
  *
  * The |EVP_AEAD_CTX_init| function initialises an |EVP_AEAD_CTX| structure and
  * performs any precomputation needed to use |aead| with |key|. The length of
  * the key, |key_len|, is given in bytes.
  *
  * The |tag_len| argument contains the length of the tags, in bytes, and allows
  * for the processing of truncated authenticators. A zero value indicates that
  * the default tag length should be used and this is defined as
  * |EVP_AEAD_DEFAULT_TAG_LENGTH| in order to make the code clear. Using
  * truncated tags increases an attacker's chance of creating a valid forgery.
  * Be aware that the attacker's chance may increase more than exponentially as
  * would naively be expected.
  *
  * When no longer needed, the initialised |EVP_AEAD_CTX| structure must be
  * passed to |EVP_AEAD_CTX_cleanup|, which will deallocate any memory used.
  *
  * With an |EVP_AEAD_CTX| in hand, one can seal and open messages. These
  * operations are intended to meet the standard notions of privacy and
  * authenticity for authenticated encryption. For formal definitions see
  * Bellare and Namprempre, "Authenticated encryption: relations among notions
  * and analysis of the generic composition paradigm," Lecture Notes in Computer
  * Science B<1976> (2000), 531–545,
  * http://www-cse.ucsd.edu/~mihir/papers/oem.html.
  *
  * When sealing messages, a nonce must be given. The length of the nonce is
  * fixed by the AEAD in use and is returned by |EVP_AEAD_nonce_length|. *The
  * nonce must be unique for all messages with the same key*. This is critically
  * important - nonce reuse may completely undermine the security of the AEAD.
  * Nonces may be predictable and public, so long as they are unique. Uniqueness
  * may be achieved with a simple counter or, if large enough, may be generated
  * randomly. The nonce must be passed into the "open" operation by the receiver
  * so must either be implicit (e.g. a counter), or must be transmitted along
  * with the sealed message.
  *
  * The "seal" and "open" operations are atomic - an entire message must be
  * encrypted or decrypted in a single call. Large messages may have to be split
  * up in order to accomodate this. When doing so, be mindful of the need not to
  * repeat nonces and the possibility that an attacker could duplicate, reorder
  * or drop message chunks. For example, using a single key for a given (large)
  * message and sealing chunks with nonces counting from zero would be secure as
  * long as the number of chunks was securely transmitted. (Otherwise an
  * attacker could truncate the message by dropping chunks from the end.)
  *
  * The number of chunks could be transmitted by prefixing it to the plaintext,
  * for example. This also assumes that no other message would ever use the same
  * key otherwise the rule that nonces must be unique for a given key would be
  * violated.
  *
  * The "seal" and "open" operations also permit additional data to be
  * authenticated via the |ad| parameter. This data is not included in the
  * ciphertext and must be identical for both the "seal" and "open" call. This
  * permits implicit context to be authenticated but may be empty if not needed.
  *
  * The "seal" and "open" operations may work in-place if the |out| and |in|
  * arguments are equal. They may also be used to shift the data left inside the
  * same buffer if |out| is less than |in|. However, |out| may not point inside
  * the input data otherwise the input may be overwritten before it has been
  * read. This situation will cause an error.
  *
  * The "seal" and "open" operations return one on success and zero on error. */


 /* AEAD algorithms. */

 /* EVP_aead_aes_128_gcm is AES-128 in Galois Counter Mode. */
 OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm(void);

 /* EVP_aead_aes_256_gcm is AES-256 in Galois Counter Mode. */
 OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm(void);

 /* EVP_aead_chacha20_poly1305 is an AEAD built from ChaCha20 and Poly1305. */
 OPENSSL_EXPORT const EVP_AEAD *EVP_aead_chacha20_poly1305(void);

 /* EVP_aead_aes_128_key_wrap is AES-128 Key Wrap mode. This should never be
  * used except to interoperate with existing systems that use this mode.
  *
  * If the nonce is emtpy then the default nonce will be used, otherwise it must
  * be eight bytes long. The input must be a multiple of eight bytes long. No
  * additional data can be given to this mode. */
 OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_key_wrap(void);

 /* EVP_aead_aes_256_key_wrap is AES-256 in Key Wrap mode. This should never be
  * used except to interoperate with existing systems that use this mode.
  *
  * See |EVP_aead_aes_128_key_wrap| for details. */
 OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_key_wrap(void);

 /* EVP_has_aes_hardware returns one if we enable hardware support for fast and
  * constant-time AES-GCM. */
 OPENSSL_EXPORT int EVP_has_aes_hardware(void);


 /* TLS specific AEAD algorithms.
  *
  * These AEAD primitives do not meet the definition of generic AEADs. They are
  * all specific to TLS in some fashion and should not be used outside of that
  * context. */

 /* EVP_aead_rc4_md5_tls uses RC4 and HMAC(MD5) in MAC-then-encrypt mode. Unlike
  * a standard AEAD, this is stateful as the RC4 state is carried from operation
  * to operation. */
 OPENSSL_EXPORT const EVP_AEAD *EVP_aead_rc4_md5_tls(void);


 /* Utility functions. */

 /* EVP_AEAD_key_length returns the length, in bytes, of the keys used by
  * |aead|. */
 OPENSSL_EXPORT size_t EVP_AEAD_key_length(const EVP_AEAD *aead);

 /* EVP_AEAD_nonce_length returns the length, in bytes, of the per-message nonce
  * for |aead|. */
 OPENSSL_EXPORT size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead);

 /* EVP_AEAD_max_overhead returns the maximum number of additional bytes added
  * by the act of sealing data with |aead|. */
 OPENSSL_EXPORT size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead);

 /* EVP_AEAD_max_tag_len returns the maximum tag length when using |aead|. This
  * is the largest value that can be passed as |tag_len| to
  * |EVP_AEAD_CTX_init|. */
 OPENSSL_EXPORT size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead);


 /* AEAD operations. */

 /* An EVP_AEAD_CTX represents an AEAD algorithm configured with a specific key
  * and message-independent IV. */
 typedef struct evp_aead_ctx_st {
   const EVP_AEAD *aead;
   /* aead_state is an opaque pointer to whatever state the AEAD needs to
    * maintain. */
   void *aead_state;
 } EVP_AEAD_CTX;

 /* EVP_AEAD_MAX_OVERHEAD contains the maximum overhead used by any AEAD
  * defined in this header. */
 #define EVP_AEAD_MAX_OVERHEAD 16

 /* EVP_AEAD_DEFAULT_TAG_LENGTH is a magic value that can be passed to
  * EVP_AEAD_CTX_init to indicate that the default tag length for an AEAD should
  * be used. */
 #define EVP_AEAD_DEFAULT_TAG_LENGTH 0

 /* EVP_AEAD_init initializes |ctx| for the given AEAD algorithm from |impl|.
  * The |impl| argument may be NULL to choose the default implementation.
  * Authentication tags may be truncated by passing a size as |tag_len|. A
  * |tag_len| of zero indicates the default tag length and this is defined as
  * EVP_AEAD_DEFAULT_TAG_LENGTH for readability.
  * Returns 1 on success. Otherwise returns 0 and pushes to the error stack. */
 OPENSSL_EXPORT int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
                                      const uint8_t *key, size_t key_len,
                                      size_t tag_len, ENGINE *impl);

 /* EVP_AEAD_CTX_cleanup frees any data allocated by |ctx|. */
 OPENSSL_EXPORT void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx);

 /* EVP_AEAD_CTX_seal encrypts and authenticates |in_len| bytes from |in| and
  * authenticates |ad_len| bytes from |ad| and writes the result to |out|. It
  * returns one on success and zero otherwise.
  *
  * This function may be called (with the same |EVP_AEAD_CTX|) concurrently with
  * itself or |EVP_AEAD_CTX_open|.
  *
  * At most |max_out_len| bytes are written to |out| and, in order to ensure
  * success, |max_out_len| should be |in_len| plus the result of
  * |EVP_AEAD_overhead|. On successful return, |*out_len| is set to the actual
  * number of bytes written.
  *
  * The length of |nonce|, |nonce_len|, must be equal to the result of
  * |EVP_AEAD_nonce_length| for this AEAD.
  *
  * |EVP_AEAD_CTX_seal| never results in a partial output. If |max_out_len| is
  * insufficient, zero will be returned. (In this case, |*out_len| is set to
  * zero.)
  *
  * If |in| and |out| alias then |out| must be <= |in|. */
 OPENSSL_EXPORT int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out,
                                      size_t *out_len, size_t max_out_len,
                                      const uint8_t *nonce, size_t nonce_len,
                                      const uint8_t *in, size_t in_len,
                                      const uint8_t *ad, size_t ad_len);

 /* EVP_AEAD_CTX_open authenticates |in_len| bytes from |in| and |ad_len| bytes
  * from |ad| and decrypts at most |in_len| bytes into |out|. It returns one on
  * success and zero otherwise.
  *
  * This function may be called (with the same |EVP_AEAD_CTX|) concurrently with
  * itself or |EVP_AEAD_CTX_seal|.
  *
  * At most |in_len| bytes are written to |out|. In order to ensure success,
  * |max_out_len| should be at least |in_len|. On successful return, |*out_len|
  * is set to the the actual number of bytes written.
  *
  * The length of |nonce|, |nonce_len|, must be equal to the result of
  * |EVP_AEAD_nonce_length| for this AEAD.
  *
  * |EVP_AEAD_CTX_open| never results in a partial output. If |max_out_len| is
  * insufficient, zero will be returned. (In this case, |*out_len| is set to
  * zero.)
  *
  * If |in| and |out| alias then |out| must be <= |in|. */
 OPENSSL_EXPORT int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out,
                                      size_t *out_len, size_t max_out_len,
                                      const uint8_t *nonce, size_t nonce_len,
                                      const uint8_t *in, size_t in_len,
                                      const uint8_t *ad, size_t ad_len);


 #if defined(__cplusplus)
 }  /* extern C */
 #endif

 #endif  /* OPENSSL_HEADER_AEAD_H */
	/* Copyright (c) 2014, Google Inc.
	*
	* Permission to use, copy, modify, and/or distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
	* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
	* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
	* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

	#ifndef OPENSSL_HEADER_AEAD_H
	#define OPENSSL_HEADER_AEAD_H

	#include <openssl/base.h>

	#if defined(__cplusplus)
	extern "C" {
	#endif


	/* Authenticated Encryption with Additional Data.
	*
	* AEAD couples confidentiality and integrity in a single primtive. AEAD
	* algorithms take a key and then can seal and open individual messages. Each
	* message has a unique, per-message nonce and, optionally, additional data
	* which is authenticated but not included in the ciphertext.
	*
	* The \|EVP_AEAD_CTX_init\| function initialises an \|EVP_AEAD_CTX\| structure and
	* performs any precomputation needed to use \|aead\| with \|key\|. The length of
	* the key, \|key_len\|, is given in bytes.
	*
	* The \|tag_len\| argument contains the length of the tags, in bytes, and allows
	* for the processing of truncated authenticators. A zero value indicates that
	* the default tag length should be used and this is defined as
	* \|EVP_AEAD_DEFAULT_TAG_LENGTH\| in order to make the code clear. Using
	* truncated tags increases an attacker's chance of creating a valid forgery.
	* Be aware that the attacker's chance may increase more than exponentially as
	* would naively be expected.
	*
	* When no longer needed, the initialised \|EVP_AEAD_CTX\| structure must be
	* passed to \|EVP_AEAD_CTX_cleanup\|, which will deallocate any memory used.
	*
	* With an \|EVP_AEAD_CTX\| in hand, one can seal and open messages. These
	* operations are intended to meet the standard notions of privacy and
	* authenticity for authenticated encryption. For formal definitions see
	* Bellare and Namprempre, "Authenticated encryption: relations among notions
	* and analysis of the generic composition paradigm," Lecture Notes in Computer
	* Science B<1976> (2000), 531–545,
	* http://www-cse.ucsd.edu/~mihir/papers/oem.html.
	*
	* When sealing messages, a nonce must be given. The length of the nonce is
	* fixed by the AEAD in use and is returned by \|EVP_AEAD_nonce_length\|. *The
	* nonce must be unique for all messages with the same key*. This is critically
	* important - nonce reuse may completely undermine the security of the AEAD.
	* Nonces may be predictable and public, so long as they are unique. Uniqueness
	* may be achieved with a simple counter or, if large enough, may be generated
	* randomly. The nonce must be passed into the "open" operation by the receiver
	* so must either be implicit (e.g. a counter), or must be transmitted along
	* with the sealed message.
	*
	* The "seal" and "open" operations are atomic - an entire message must be
	* encrypted or decrypted in a single call. Large messages may have to be split
	* up in order to accomodate this. When doing so, be mindful of the need not to
	* repeat nonces and the possibility that an attacker could duplicate, reorder
	* or drop message chunks. For example, using a single key for a given (large)
	* message and sealing chunks with nonces counting from zero would be secure as
	* long as the number of chunks was securely transmitted. (Otherwise an
	* attacker could truncate the message by dropping chunks from the end.)
	*
	* The number of chunks could be transmitted by prefixing it to the plaintext,
	* for example. This also assumes that no other message would ever use the same
	* key otherwise the rule that nonces must be unique for a given key would be
	* violated.
	*
	* The "seal" and "open" operations also permit additional data to be
	* authenticated via the \|ad\| parameter. This data is not included in the
	* ciphertext and must be identical for both the "seal" and "open" call. This
	* permits implicit context to be authenticated but may be empty if not needed.
	*
	* The "seal" and "open" operations may work in-place if the \|out\| and \|in\|
	* arguments are equal. They may also be used to shift the data left inside the
	* same buffer if \|out\| is less than \|in\|. However, \|out\| may not point inside
	* the input data otherwise the input may be overwritten before it has been
	* read. This situation will cause an error.
	*
	* The "seal" and "open" operations return one on success and zero on error. */


	/* AEAD algorithms. */

	/* EVP_aead_aes_128_gcm is AES-128 in Galois Counter Mode. */
	OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm(void);

	/* EVP_aead_aes_256_gcm is AES-256 in Galois Counter Mode. */
	OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm(void);

	/* EVP_aead_chacha20_poly1305 is an AEAD built from ChaCha20 and Poly1305. */
	OPENSSL_EXPORT const EVP_AEAD *EVP_aead_chacha20_poly1305(void);

	/* EVP_aead_aes_128_key_wrap is AES-128 Key Wrap mode. This should never be
	* used except to interoperate with existing systems that use this mode.
	*
	* If the nonce is emtpy then the default nonce will be used, otherwise it must
	* be eight bytes long. The input must be a multiple of eight bytes long. No
	* additional data can be given to this mode. */
	OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_key_wrap(void);

	/* EVP_aead_aes_256_key_wrap is AES-256 in Key Wrap mode. This should never be
	* used except to interoperate with existing systems that use this mode.
	*
	* See \|EVP_aead_aes_128_key_wrap\| for details. */
	OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_key_wrap(void);

	/* EVP_has_aes_hardware returns one if we enable hardware support for fast and
	* constant-time AES-GCM. */
	OPENSSL_EXPORT int EVP_has_aes_hardware(void);


	/* TLS specific AEAD algorithms.
	*
	* These AEAD primitives do not meet the definition of generic AEADs. They are
	* all specific to TLS in some fashion and should not be used outside of that
	* context. */

	/* EVP_aead_rc4_md5_tls uses RC4 and HMAC(MD5) in MAC-then-encrypt mode. Unlike
	* a standard AEAD, this is stateful as the RC4 state is carried from operation
	* to operation. */
	OPENSSL_EXPORT const EVP_AEAD *EVP_aead_rc4_md5_tls(void);


	/* Utility functions. */

	/* EVP_AEAD_key_length returns the length, in bytes, of the keys used by
	* \|aead\|. */
	OPENSSL_EXPORT size_t EVP_AEAD_key_length(const EVP_AEAD *aead);

	/* EVP_AEAD_nonce_length returns the length, in bytes, of the per-message nonce
	* for \|aead\|. */
	OPENSSL_EXPORT size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead);

	/* EVP_AEAD_max_overhead returns the maximum number of additional bytes added
	* by the act of sealing data with \|aead\|. */
	OPENSSL_EXPORT size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead);

	/* EVP_AEAD_max_tag_len returns the maximum tag length when using \|aead\|. This
	* is the largest value that can be passed as \|tag_len\| to
	* \|EVP_AEAD_CTX_init\|. */
	OPENSSL_EXPORT size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead);


	/* AEAD operations. */

	/* An EVP_AEAD_CTX represents an AEAD algorithm configured with a specific key
	* and message-independent IV. */
	typedef struct evp_aead_ctx_st {
	const EVP_AEAD *aead;
	/* aead_state is an opaque pointer to whatever state the AEAD needs to
	* maintain. */
	void *aead_state;
	} EVP_AEAD_CTX;

	/* EVP_AEAD_MAX_OVERHEAD contains the maximum overhead used by any AEAD
	* defined in this header. */
	#define EVP_AEAD_MAX_OVERHEAD 16

	/* EVP_AEAD_DEFAULT_TAG_LENGTH is a magic value that can be passed to
	* EVP_AEAD_CTX_init to indicate that the default tag length for an AEAD should
	* be used. */
	#define EVP_AEAD_DEFAULT_TAG_LENGTH 0

	/* EVP_AEAD_init initializes \|ctx\| for the given AEAD algorithm from \|impl\|.
	* The \|impl\| argument may be NULL to choose the default implementation.
	* Authentication tags may be truncated by passing a size as \|tag_len\|. A
	* \|tag_len\| of zero indicates the default tag length and this is defined as
	* EVP_AEAD_DEFAULT_TAG_LENGTH for readability.
	* Returns 1 on success. Otherwise returns 0 and pushes to the error stack. */
	OPENSSL_EXPORT int EVP_AEAD_CTX_init(EVP_AEAD_CTX ctx, const EVP_AEAD aead,
	const uint8_t *key, size_t key_len,
	size_t tag_len, ENGINE *impl);

	/* EVP_AEAD_CTX_cleanup frees any data allocated by \|ctx\|. */
	OPENSSL_EXPORT void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx);

	/* EVP_AEAD_CTX_seal encrypts and authenticates \|in_len\| bytes from \|in\| and
	* authenticates \|ad_len\| bytes from \|ad\| and writes the result to \|out\|. It
	* returns one on success and zero otherwise.
	*
	* This function may be called (with the same \|EVP_AEAD_CTX\|) concurrently with
	* itself or \|EVP_AEAD_CTX_open\|.
	*
	* At most \|max_out_len\| bytes are written to \|out\| and, in order to ensure
	* success, \|max_out_len\| should be \|in_len\| plus the result of
	* \|EVP_AEAD_overhead\|. On successful return, \|*out_len\| is set to the actual
	* number of bytes written.
	*
	* The length of \|nonce\|, \|nonce_len\|, must be equal to the result of
	* \|EVP_AEAD_nonce_length\| for this AEAD.
	*
	* \|EVP_AEAD_CTX_seal\| never results in a partial output. If \|max_out_len\| is
	* insufficient, zero will be returned. (In this case, \|*out_len\| is set to
	* zero.)
	*
	* If \|in\| and \|out\| alias then \|out\| must be <= \|in\|. */
	OPENSSL_EXPORT int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX ctx, uint8_t out,
	size_t *out_len, size_t max_out_len,
	const uint8_t *nonce, size_t nonce_len,
	const uint8_t *in, size_t in_len,
	const uint8_t *ad, size_t ad_len);

	/* EVP_AEAD_CTX_open authenticates \|in_len\| bytes from \|in\| and \|ad_len\| bytes
	* from \|ad\| and decrypts at most \|in_len\| bytes into \|out\|. It returns one on
	* success and zero otherwise.
	*
	* This function may be called (with the same \|EVP_AEAD_CTX\|) concurrently with
	* itself or \|EVP_AEAD_CTX_seal\|.
	*
	* At most \|in_len\| bytes are written to \|out\|. In order to ensure success,
	* \|max_out_len\| should be at least \|in_len\|. On successful return, \|*out_len\|
	* is set to the the actual number of bytes written.
	*
	* The length of \|nonce\|, \|nonce_len\|, must be equal to the result of
	* \|EVP_AEAD_nonce_length\| for this AEAD.
	*
	* \|EVP_AEAD_CTX_open\| never results in a partial output. If \|max_out_len\| is
	* insufficient, zero will be returned. (In this case, \|*out_len\| is set to
	* zero.)
	*
	* If \|in\| and \|out\| alias then \|out\| must be <= \|in\|. */
	OPENSSL_EXPORT int EVP_AEAD_CTX_open(const EVP_AEAD_CTX ctx, uint8_t out,
	size_t *out_len, size_t max_out_len,
	const uint8_t *nonce, size_t nonce_len,
	const uint8_t *in, size_t in_len,
	const uint8_t *ad, size_t ad_len);


	#if defined(__cplusplus)
	} /* extern C */
	#endif

	#endif /* OPENSSL_HEADER_AEAD_H */