/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/**

 */

import javax.crypto.Cipher;

import java.security.GeneralSecurityException;

import java.security.KeyPairGenerator;

import java.security.KeyPair;

import java.security.Key;

public class RSAEncryptDecrypt {

    public static final byte[] PLAINTEXT = {1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6};

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

        KeyPairGenerator generator =

            KeyPairGenerator.getInstance("RSA", "SunMSCAPI");

        KeyPair keyPair = generator.generateKeyPair();

        Key publicKey = keyPair.getPublic();

        Key privateKey = keyPair.getPrivate();

        Cipher cipher = null;

        try {

            cipher = Cipher.getInstance("RSA", "SunMSCAPI");

        } catch (GeneralSecurityException e) {

            System.out.println("Cipher not supported by provider, skipping...");

            return;

        }

        cipher.init(Cipher.ENCRYPT_MODE, publicKey);

        displayBytes("Plaintext data:", PLAINTEXT);

        byte[] data = cipher.doFinal(PLAINTEXT);

        displayBytes("Encrypted data:", data);

        cipher.init(Cipher.DECRYPT_MODE, privateKey);

        data = cipher.doFinal(data);

        displayBytes("Decrypted data:", data);

    }

    private static void displayBytes(String label, byte[] bytes) {

        System.out.println(label + " [length=" + bytes.length + "]");

        for (byte b : bytes) {

            System.out.print("0x" + Integer.toHexString(b & 0xFF) + " ");

        }

        System.out.println();

    }

}