random.hpp

/*
   Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.

   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; version 2 of the License.

   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; see the file COPYING. If not, write to the
   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
   MA  02110-1301  USA.
*/

/* random.hpp provides a crypto secure Random Number Generator using an OS
   specific seed
*/


#ifndef TAO_CRYPT_RANDOM_HPP
#define TAO_CRYPT_RANDOM_HPP

#include "arc4.hpp"
#include "error.hpp"

namespace TaoCrypt {


// OS specific seeder
class OS_Seed {
public:
    OS_Seed();
    ~OS_Seed();

    void   GenerateSeed(byte*, word32 sz);
    Error  GetError() const { return error_; }
private:
#if defined(_WIN32)
    #if defined(_WIN64)
        typedef unsigned __int64 ProviderHandle;
        // type HCRYPTPROV, avoid #include <windows.h>
    #else
        typedef unsigned long ProviderHandle;
    #endif
    ProviderHandle handle_;
#else
    int fd_;
#endif
    Error error_;

    OS_Seed(const OS_Seed&);              // hide copy
    OS_Seed& operator=(const OS_Seed&);   // hide assign
};


// secure Random Nnumber Generator
class RandomNumberGenerator {
public:
    RandomNumberGenerator();
    ~RandomNumberGenerator() {}

    void GenerateBlock(byte*, word32 sz);
    byte GenerateByte();

    ErrorNumber GetError() const { return seed_.GetError().What(); }
private:
    OS_Seed seed_;
    ARC4    cipher_;

    RandomNumberGenerator(const RandomNumberGenerator&);           // hide copy
    RandomNumberGenerator operator=(const RandomNumberGenerator&); // && assign
};




}  // namespace

#endif // TAO_CRYPT_RANDOM_HPP