chatapplication.genrateRSAkeys.java Source code

Introduction

Here is the source code for chatapplication.genrateRSAkeys.java

Source

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package chatapplication;

import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

/**
 *
 * @author chaitanya
 */
public class genrateRSAkeys {

    public static void main(String args[]) throws NoSuchAlgorithmException, Exception {

        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        KeyFactory fact = KeyFactory.getInstance("RSA");
        kpg.initialize(2048);
        KeyPair kp = kpg.genKeyPair();
        PublicKey publicKey = kp.getPublic();
        PrivateKey privateKey = kp.getPrivate();

        byte[] data = publicKey.getEncoded();
        String d1 = new String(data);
        String dl = Arrays.toString(data);
        String message = "HI";
        // String encKey = new String(publicKey);
        // byte[] publicK = Base64.getDecoder().decode(data);
        //byte[] publicBytes = Base64.getDecoder().decode(convertedPublic);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(data);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey pubKey = keyFactory.generatePublic(keySpec);
        Provider bcProvider = new BouncyCastleProvider();
        byte encryptedMessage[] = RSAencrypt(message, pubKey);
        byte decryptedMessage[] = RSAdecrypt(encryptedMessage, privateKey);
        System.out.println("Message" + new String(decryptedMessage));
    }

    public static byte[] RSAencrypt(String plainText, PublicKey pKey) throws Exception {

        Provider bcProvider = new BouncyCastleProvider();
        Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding", bcProvider);

        cipher.init(Cipher.ENCRYPT_MODE, pKey);
        byte[] c = cipher.doFinal(plainText.getBytes("UTF-8"));
        return c;
    }

    public static byte[] RSAdecrypt(byte[] res1, PrivateKey pk) throws NoSuchAlgorithmException,
            NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        Provider bcProvider = new BouncyCastleProvider();
        Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding", bcProvider);
        cipher.init(Cipher.DECRYPT_MODE, pk);
        byte[] key = cipher.doFinal(res1);
        return key;

    }

}