import java.security.*;
import java.security.spec.InvalidParameterSpecException;
import javax.crypto.*;
import javax.crypto.spec.DHParameterSpec;


class DHKeyGen{	
	private int size;	
	private PrivateKey privateKey;
	private PublicKey publicKey;
	
	DHKeyGen(){
		size = 1024;
		
		try{
			AlgorithmParameterGenerator paramGen = 
				AlgorithmParameterGenerator.getInstance("DH");
			paramGen.init(size);
			
			AlgorithmParameters params = 
                                paramGen.generateParameters();
			
			DHParameterSpec dhSpec
				= (DHParameterSpec)params.getParameterSpec(DHParameterSpec.class);
			
			KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("DH");
			keyPairGen.initialize(dhSpec);
			
			KeyPair keyPair = keyPairGen.generateKeyPair();
			
			privateKey = keyPair.getPrivate();
			publicKey = keyPair.getPublic();
			
		} catch(NoSuchAlgorithmException e){
			e.printStackTrace();
		} catch (InvalidParameterSpecException e) {
			e.printStackTrace();
		} catch (InvalidAlgorithmParameterException e) {
			e.printStackTrace();
		}
	}	
}