crypto.hpp

Go to the documentation of this file.

//*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2052 Denis Corbin
//
// 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.
//
// 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.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//
// to contact the author : http://dar.linux.free.fr/email.html
/*********************************************************************/


#ifndef CRYPTO_HPP
#define CRYPTO_HPP

extern "C"
{
#if HAVE_GCRYPT_H
#include <gcrypt.h>
#endif
}

#include "../my_config.h"
#include <string>

#include "tronconneuse.hpp"
#include "header_version.hpp"
#include "secu_string.hpp"

namespace libdar
{


    enum crypto_algo
    {
        crypto_none,          
        crypto_scrambling,    
        crypto_blowfish,      
        crypto_aes256,        
        crypto_twofish256,    
        crypto_serpent256,    
        crypto_camellia256    
    };


    extern void crypto_split_algo_pass(const secu_string & all, crypto_algo & algo, secu_string & pass);


        //
        //

    class crypto_sym : public tronconneuse
    {
    public:
        crypto_sym(U_32 block_size,
                   const secu_string & password,
                   generic_file & encrypted_side,
                   bool no_initial_shift,
                   const archive_version & reading_ver,
                   crypto_algo algo); //< must be a symetrical algo (else an exception is thrown)
        ~crypto_sym() { detruit(); };

    protected:
        U_32 encrypted_block_size_for(U_32 clear_block_size);
        U_32 clear_block_allocated_size_for(U_32 clear_block_size);
        U_32 encrypt_data(const infinint & block_num,
                          const char *clear_buf, const U_32 clear_size, const U_32 clear_allocated,
                          char *crypt_buf, U_32 crypt_size);
        U_32 decrypt_data(const infinint & block_num,
                          const char *crypt_buf, const U_32 crypt_size,
                          char *clear_buf, U_32 clear_size);

    private:
#if CRYPTO_AVAILABLE
        gcry_cipher_hd_t clef;       //< used to encrypt/decrypt the data
        gcry_cipher_hd_t essiv_clef; //< used to build the Initialization Vector
#endif
        size_t algo_block_size;         //< the block size of the algorithm
        unsigned char *ivec;            //< algo_block_size allocated in secure memory to be used as Initial Vector
        U_I algo_id;                    //< algo ID in libgcrypt
        archive_version reading_version;

        secu_string pkcs5_pass2key(const secu_string & password,         //< human provided password
                                   const std::string & salt,             //< salt string
                                   U_I iteration_count,                  //< number of time to shake the melange
                                   U_I output_length);                   //< length of the string to return
        void dar_set_essiv(const secu_string & key);                     //< assign essiv from the given (hash) string
        void make_ivec(const infinint & ref, unsigned char *ivec, U_I size);
        void self_test(void);
        void detruit();
    };


} // end of namespace

#endif