main.java

ElGamal method is an aymetric method to crypt message. You can use ElGamal to crypt the key session

package elgamal;

import java.math.BigInteger;
import java.util.Random;
public class Main {

  
    public static void main(String[] args) {
        java.security.SecureRandom random=new java.security.SecureRandom();
        Parameter params=new Parameter(1024,100);//,random);
        KeyPairGenerator clef=new KeyPairGenerator(new Random(),params);
        PrivateKey x=clef.getPrivate();
        PublicKey y=clef.getPublic();
        
        /********Chiffrement ElGamal*************/
        String message="Je suis Salem Mathlouthi. Ceci est un test de la m閠hode de chiffrement ElGamal";
        byte[]bm=message.getBytes();
        BigInteger plaintext=new BigInteger(bm);
        
        ElGamalCrypt elgamal=new ElGamalCrypt(params);
        
        BigInteger []ciphertext=elgamal.chiffre(plaintext, y);
        
        System.out.println("p= "+params.getP().toString(16));
        System.out.println("g= "+params.getG().toString(16));
        System.out.println("x= "+x.getX().toString(16));
        System.out.println("y= "+y.getY().toString(16));
        
        System.out.println("c1= "+ciphertext[0].toString(16));
        System.out.println("c2= "+ciphertext[1].toString(16));
        
        BigInteger clair=elgamal.dechiffre(ciphertext, x);
        
        byte[]bc=clair.toByteArray();
        
        String str=new String(bc);
        
        System.out.println(str); 
        
        ElGamalSign sign=new ElGamalSign(params,x,bm);
        
        System.out.println("r= "+sign.getR().toString(16));
        System.out.println("s= "+sign.getS().toString(16));
        
        ElGamalVerify verif=new ElGamalVerify(params,y,bm,sign.getR(),sign.getS());
        
        if(verif.getVerify())System.out.println("Signature accept閑");
        else System.out.println("Signature rejet閑");
        

    }

}