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// -*- c++ -*-
//
// $Id: crypt.h 2850 2009-09-01 10:53:25Z rafi $
//
// Copyright (C) 2008, 2009 Rafael Ostertag
//
// This file is part of YAPET.
//
// YAPET 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 3 of the License, or (at your option) any later
// version.
//
// YAPET 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.
//
// You should have received a copy of the GNU General Public License along with
// YAPET. If not, see <http://www.gnu.org/licenses/>.
//
// Additional permission under GNU GPL version 3 section 7
//
// If you modify this program, or any covered work, by linking or combining it
// with the OpenSSL project's OpenSSL library (or a modified version of that
// library), containing parts covered by the terms of the OpenSSL or SSLeay
// licenses, Rafael Ostertag grants you additional permission to convey the
// resulting work. Corresponding Source for a non-source form of such a
// combination shall include the source code for the parts of OpenSSL used as
// well as that of the covered work.
//
#ifndef _CRYPT_H
#define _CRYPT_H
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef HAVE_INTTYPES_H
# include <inttypes.h>
#endif
#include "../intl.h"
#include <openssl/evp.h>
#include "yapetexception.h"
#include "key.h"
#include "bdbuffer.h"
#include "record.h"
namespace YAPET {
/**
* @brief Encrypts and decrypts data
*
* This class encrypts and decrypts data using the key provided by
* \c Key.
*
* Encrypted data is returned in \c BDBuffer. Decrypted data is
* returned as a struct as defined in \c structs.h using the
* template \c Record.
*
* Currently, the blowfish algorithm in CBC mode from the openssl
* library is used for encryption and decryption. The class itself
* does not have any encryption/decryption logic.
*
* @sa Key, BDBuffer, Record
*/
class Crypt {
private:
/**
* @brief Pointer to the cipher used for
* encryption/decryption
*
* Pointer the cipher implemented in the openssl
* library. Currently, blowfish is used for
* encryption/decryption.
*/
const EVP_CIPHER* cipher;
/**
* @brief Length of the initialization vector
*
* Length of the initialization vector as expected by the
* cipher implementation in bytes.
*/
uint32_t iv_length;
/**
* @brief Length of the encryption/decryption key
*
* Length of the encryption/decryption key as expected by
* the cipher implementation in bytes.
*/
uint32_t key_length;
/**
* @brief the key used for encryption/decryption
*
* The key used for encryption/decryption.
*/
Key key;
public:
//! Constructor
Crypt (const Key& k) throw (YAPETException);
Crypt (const Crypt& c);
inline ~Crypt() {}
/**
* @brief Returns the length of the initialization vector
*
* Returns the length in bytes of the initialization
* vector the cipher algorithm expects
*
* @return the length of the initialization vector in
* bytes.
*/
inline uint32_t getIVLength() const {
return iv_length;
}
/**
* @brief Returns the length of the key
*
* Returns the length in bytes of the key the cipher
* algorithm expects.
*
* @return the length of the key in bytes.
*/
inline uint32_t getKeyLength() const {
return key_length;
}
/**
* @brief Encrypts data
*
* Encrypts the data provided in \c data which has to be
* an instance of the \c Record template.
*
* The encrypted data is returned as \c BDBuffer with the
* size set exactly to the size of the encrypted data. The
* memory occupied by this object has to be freed by the
* caller.
*
* @param data the data to be encrypted.
*
* @return pointer to a \c BDBuffer holding the encrypted
* data. The caller is responsible for freeing the memory
* occupied by the object returned.
*
* @throw YAPETException
*
* @throw YAPETEncryptionException
*
* @sa Record, BDBuffer
*/
template<class T>
BDBuffer* encrypt (const Record<T>& data)
throw (YAPETException, YAPETEncryptionException) {
if (key.ivec_size() != iv_length)
throw YAPETException (_ ("IVec length missmatch") );
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init (&ctx);
int retval = EVP_EncryptInit_ex (&ctx,
cipher,
NULL,
key,
key.getIVec() );
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
throw YAPETEncryptionException (_ ("Error initializing encryption engine") );
}
retval = EVP_CIPHER_CTX_set_key_length (&ctx, key.size() );
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
throw YAPETException (_ ("Error setting the key length") );
}
BDBuffer* encdata =
new BDBuffer (data.size() + EVP_MAX_BLOCK_LENGTH);
int outlen;
retval = EVP_EncryptUpdate (&ctx,
*encdata,
&outlen,
data,
data.size() );
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
delete encdata;
throw YAPETEncryptionException (_ ("Error encrypting data") );
}
int tmplen;
retval = EVP_EncryptFinal_ex (&ctx,
encdata->at (outlen),
&tmplen);
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
delete encdata;
throw YAPETEncryptionException (_ ("Error finalizing encryption") );
}
encdata->resize (outlen + tmplen);
EVP_CIPHER_CTX_cleanup (&ctx);
return encdata;
}
/**
* @brief Decrypts data
*
* Decrypts the data supplied in the \c BDBuffer. It
* returns the decrypted data as a \c Record of the
* specified type.
*
* The \c Record has to be freed by the caller.
*
* @param data the \c BDBuffer to decrypt.
*
* @return pointer to a \c Record of the specified type,
* holding the decrypted data. The caller is responsible
* for freeing the memory occupied by the object returned.
*
* @throw YAPETException
*
* @throw YAPETEncryptionException
*
* @sa Record, BDBuffer
*/
template<class T>
Record<T>* decrypt (const BDBuffer& data)
throw (YAPETException, YAPETEncryptionException) {
if ( ( (unsigned int) key.ivec_size() ) != iv_length)
throw YAPETException (_ ("IVec length missmatch") );
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init (&ctx);
int retval = EVP_DecryptInit_ex (&ctx,
cipher,
NULL,
key,
key.getIVec() );
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
throw YAPETEncryptionException (_ ("Error initializing encryption engine") );
}
retval = EVP_CIPHER_CTX_set_key_length (&ctx, key.size() );
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
throw YAPETException (_ ("Error setting the key length") );
}
BDBuffer* decdata = new BDBuffer (data.size() );
int outlen;
retval = EVP_DecryptUpdate (&ctx,
*decdata,
&outlen,
data,
data.size() );
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
delete decdata;
throw YAPETEncryptionException (_ ("Error decrypting data") );
}
int tmplen;
retval = EVP_DecryptFinal_ex (&ctx,
decdata->at (outlen),
&tmplen);
if (retval == 0) {
EVP_CIPHER_CTX_cleanup (&ctx);
delete decdata;
throw YAPETEncryptionException (_ ("Error finalizing decryption") );
}
decdata->resize (outlen + tmplen);
EVP_CIPHER_CTX_cleanup (&ctx);
Record<T>* r = NULL;
try {
r = new Record<T>;
*r = *decdata;
} catch (...) {
if ( r != NULL)
delete r;
delete decdata;
throw;
}
delete decdata;
return r;
}
const Crypt& operator= (const Crypt& c);
};
}
#endif // _CRYPT_H
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