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/*
* Copyright (C) 2005-2006 Martin Willi
* Copyright (C) 2005 Jan Hutter
* Hochschule fuer Technik Rapperswil
*
* 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.
*
* $Id: encryption_payload.h 3589 2008-03-13 14:14:44Z martin $
*/
/**
* @defgroup encryption_payload encryption_payload
* @{ @ingroup payloads
*/
#ifndef ENCRYPTION_PAYLOAD_H_
#define ENCRYPTION_PAYLOAD_H_
typedef struct encryption_payload_t encryption_payload_t;
#include <library.h>
#include <crypto/crypters/crypter.h>
#include <crypto/signers/signer.h>
#include <encoding/payloads/payload.h>
#include <utils/linked_list.h>
/**
* Encrpytion payload length in bytes without IV and following data.
*/
#define ENCRYPTION_PAYLOAD_HEADER_LENGTH 4
/**
* The encryption payload as described in RFC section 3.14.
*
* Before any crypt/decrypt/sign/verify operation can occur,
* the transforms must be set. After that, a parsed encryption payload
* can be decrypted, which also will parse the contained payloads.
* Encryption is done the same way, added payloads will get generated
* and then encrypted.
* For signature building, there is the FULL packet needed. Meaning it
* must be builded after generation of all payloads and the encryption
* of the encryption payload.
* Signature verificatin is done before decryption.
*/
struct encryption_payload_t {
/**
* Implements payload_t interface.
*/
payload_t payload_interface;
/**
* Creates an iterator for all contained payloads.
*
* iterator_t object has to get destroyed by the caller.
*
* @param forward iterator direction (TRUE: front to end)
* return created iterator_t object
*/
iterator_t *(*create_payload_iterator) (encryption_payload_t *this, bool forward);
/**
* Adds a payload to this encryption payload.
*
* @param payload payload_t object to add
*/
void (*add_payload) (encryption_payload_t *this, payload_t *payload);
/**
* Reove the last payload in the contained payload list.
*
* @param payload removed payload
* @return
* - SUCCESS, or
* - NOT_FOUND if list empty
*/
status_t (*remove_first_payload) (encryption_payload_t *this, payload_t **payload);
/**
* Get the number of payloads.
*
* @return number of contained payloads
*/
size_t (*get_payload_count) (encryption_payload_t *this);
/**
* Set transforms to use.
*
* To decryption, encryption, signature building and verifying,
* the payload needs a crypter and a signer object.
*
* @warning Do NOT call this function again after encryption, since
* the signer must be the same while encrypting and signature building!
*
* @param crypter crypter_t to use for data de-/encryption
* @param signer signer_t to use for data signing/verifying
*/
void (*set_transforms) (encryption_payload_t *this, crypter_t *crypter, signer_t *signer);
/**
* Generate and encrypt contained payloads.
*
* This function generates the content for added payloads
* and encrypts them. Signature is not built, since we need
* additional data (the full message).
*
* @return SUCCESS, or INVALID_STATE if transforms not set
*/
status_t (*encrypt) (encryption_payload_t *this);
/**
* Decrypt and parse contained payloads.
*
* This function decrypts the contained data. After,
* the payloads are parsed internally and are accessible
* via the iterator.
*
* @return
* - SUCCESS, or
* - INVALID_STATE if transforms not set, or
* - FAILED if data is invalid
*/
status_t (*decrypt) (encryption_payload_t *this);
/**
* Build the signature.
*
* The signature is built over the FULL message, so the header
* and every payload (inclusive this one) must already be generated.
* The generated message is supplied via the data paramater.
*
* @param data chunk contains the already generated message
* @return
* - SUCCESS, or
* - INVALID_STATE if transforms not set
*/
status_t (*build_signature) (encryption_payload_t *this, chunk_t data);
/**
* Verify the signature.
*
* Since the signature is built over the full message, we need
* this data to do the verification. The message data
* is supplied via the data argument.
*
* @param data chunk contains the message
* @return
* - SUCCESS, or
* - FAILED if signature invalid, or
* - INVALID_STATE if transforms not set
*/
status_t (*verify_signature) (encryption_payload_t *this, chunk_t data);
/**
* Destroys an encryption_payload_t object.
*/
void (*destroy) (encryption_payload_t *this);
};
/**
* Creates an empty encryption_payload_t object.
*
* @return encryption_payload_t object
*/
encryption_payload_t *encryption_payload_create(void);
#endif /*ENCRYPTION_PAYLOAD_H_ @} */
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