Vigenere.h

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/***************************************************************************
 *   Copyright (C) 2007 by Pierre Schmitt, Ludovic Giacomello, Nhi Ly   *
 *      *
 *                                                                         *
 *   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.             *
 ***************************************************************************/


#ifndef VIGENERE_H
#define VIGENERE_H

#include <iostream>
#include <cstdlib>


using namespace std;

class Vigenere : public Cryptage{
public:
        Vigenere(){};
        void SetCle(string cle){ 
                mCle=cle;
        }

        string Crypter(string msg) const{
                string cryptage=msg;
                int codeAsciiMsg, codeAsciiCle;
                for(int i=0; i<msg.length(); i++){
                        codeAsciiMsg=msg[i];
                        codeAsciiCle=mCle[i%mCle.length()];
                        cryptage[i]=codeAsciiMsg+codeAsciiCle;
                        if(cryptage[i]==0) cerr<<"CODE VAUT ZERO pour le caractère n°"<<i<<" en clair:"<<codeAsciiMsg<<" avec la clé valant "<<codeAsciiCle<<endl;
                }
                return cryptage;
        }
        string Decrypter(string msg) const{
                string cryptage=msg;
                int codeAsciiMsg, codeAsciiCle;
                for(int i=0; i<msg.length(); i++){
                        codeAsciiMsg=msg[i];
                        codeAsciiCle=mCle[i%mCle.length()];
                        cryptage[i]=codeAsciiMsg-codeAsciiCle;
                }
                return cryptage;
        }

        void Test(){
                Vigenere v;
                v.SetCle("testdeVigenere");
                cout<<"Cryptage de \"Test\""<<endl;
                cout<<v.Crypter("Test")<<endl;
                cout<<"Décryptage du cryptage de \"Test\""<<endl;
                cout<<v.Decrypter(v.Crypter("Test"))<<endl;             
        }
private:
        string mCle;
};

#endif

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