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/*
* Copyright (C) 2014 Martin Willi
* Copyright (C) 2014 revosec AG
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
/**
* @defgroup tls_aead tls_aead
* @{ @ingroup tls
*/
#ifndef TLS_AEAD_H_
#define TLS_AEAD_H_
typedef struct tls_aead_t tls_aead_t;
#include "tls.h"
/**
* TLS specific AEAD interface, includes padding.
*
* As TLS uses sign-then-encrypt instead of the more modern encrypt-then-sign,
* we can't directly abstract traditional transforms using our aead_t interface.
* With traditional transforms, the AEAD operation has to manage padding, as
* the MAC is calculated over unpadded data.
*/
struct tls_aead_t {
/**
* Encrypt and sign a TLS record.
*
* The plain data chunk gets freed on success, and the data chunk
* gets updated with a new allocation of the encrypted data.
* If next_iv is given, it must contain the IV for this operation. It
* gets updated to the IV for the next record.
*
* @param version TLS version
* @param type TLS content type
* @param seq record sequence number
* @param data data to encrypt, encryption result
* @return TRUE if successfully encrypted
*/
bool (*encrypt)(tls_aead_t *this, tls_version_t version,
tls_content_type_t type, u_int64_t seq, chunk_t *data);
/**
* Decrypt and verify a TLS record.
*
* The passed encrypted data chunk gets updated to the decrypted record
* length, decryption is done inline.
*
* @param version TLS version
* @param type TLS content type
* @param seq record sequence number
* @param data data to decrypt, decrypted result
* @return TRUE if successfully decrypted
*/
bool (*decrypt)(tls_aead_t *this, tls_version_t version,
tls_content_type_t type, u_int64_t seq, chunk_t *data);
/**
* Get the authentication key size.
*
* @return key size, in bytes, 0 if not used
*/
size_t (*get_mac_key_size)(tls_aead_t *this);
/**
* Get the encrytion key size, if used.
*
* @return key size, in bytes, 0 if not used
*/
size_t (*get_encr_key_size)(tls_aead_t *this);
/**
* Get the size of implicit IV (or AEAD salt), if used.
*
* @return IV/salt size, in bytes, 0 if not used
*/
size_t (*get_iv_size)(tls_aead_t *this);
/**
* Set the keys used by an AEAD transform.
*
* @param mac authentication key, if used
* @param encr encryption key, if used
* @param iv initial implicit IV or AEAD salt, if any
* @return TRUE if key valid and set
*/
bool (*set_keys)(tls_aead_t *this, chunk_t mac, chunk_t ecnr, chunk_t iv);
/**
* Destroy a tls_aead_t.
*/
void (*destroy)(tls_aead_t *this);
};
/**
* Create a tls_aead instance using traditional transforms, explicit IV.
*
* An explicit IV means that the IV is prepended to each TLS record. This is
* the mechanism used in TLS 1.1 and newer.
*
* @param mac integrity protection algorithm
* @param encr encryption algorithm
* @param encr_size encryption key size, in bytes
* @return TLS AEAD transform
*/
tls_aead_t *tls_aead_create_explicit(integrity_algorithm_t mac,
encryption_algorithm_t encr, size_t encr_size);
/**
* Create a tls_aead instance using traditional transforms, implicit IV.
*
* An implicit IV uses a first IV derived from the TLS keymat, which then
* gets replaced by the last encrypted records tail. This is the mechanism
* used for TLS 1.0 and older.
*
* @param mac integrity protection algorithm
* @param encr encryption algorithm
* @param encr_size encryption key size, in bytes
* @return TLS AEAD transform
*/
tls_aead_t *tls_aead_create_implicit(integrity_algorithm_t mac,
encryption_algorithm_t encr, size_t encr_size);
/**
* Create a tls_aead instance using NULL encryption.
*
* As no IV is involved with null encryption, this AEAD works with any
* version of TLS.
*
* @param mac integrity protection algorithm
* @return TLS AEAD transform
*/
tls_aead_t *tls_aead_create_null(integrity_algorithm_t mac);
/**
* Create a tls_aead instance using real a AEAD cipher.
*
* @param encr AEAD encryption algorithm
* @param encr_size encryption key size, in bytes
* @return TLS AEAD transform
*/
tls_aead_t *tls_aead_create_aead(encryption_algorithm_t encr, size_t encr_size);
#endif /** TLS_AEAD_H_ @}*/
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