/*
 * Copyright (c) 1998, Oracle and/or its affiliates. All rights reserved.
 * 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.
 */

/* @test
 * @bug 4102896
 * @summary Make sure that a SecureRandom object can be serialized
 */

import java.security.*;
import java.io.*;

public class Serialize {

    public static void main(String args[]) throws Exception {
        for (String alg: new String[]{
                "SHA1PRNG", "DRBG", "Hash_DRBG", "HMAC_DRBG", "CTR_DRBG"}) {
            System.out.println("Testing " + alg);

            // Even unseeded object can be serialized and deserialized
            SecureRandom s1 = getInstance(alg);
            revive(s1).nextInt();
            if (alg.contains("DRBG")) {
                revive(s1).reseed();
            }

            // After seeded, deserialized object should emit same random data
            s1 = getInstance(alg);
            s1.nextInt();    // state set
            SecureRandom s2 = revive(s1);
            int n1 = s1.nextInt();
            int n2 = s2.nextInt();
            if (n1 != n2) {
                throw new Exception();
            }

            // Or seeded with user-provided data
            s1.setSeed(42);
            s2.setSeed(42);
            n1 = s1.nextInt();
            n2 = s2.nextInt();
            if (n1 != n2) {
                throw new Exception();
            }

            // But not after automatic reseed
            if (alg.contains("DRBG")) {
                s1.reseed();
                s2.reseed();
                n1 = s1.nextInt();
                n2 = s2.nextInt();
                if (n1 == n2) {
                    throw new Exception();
                }
            }
        }
    }

    private static SecureRandom getInstance(String alg) throws Exception {
        if (alg.equals("SHA1PRNG") || alg.equals("DRBG")) {
            return SecureRandom.getInstance(alg);
        } else {
            String old = Security.getProperty("drbg");
            try {
                Security.setProperty("drbg", alg);
                return SecureRandom.getInstance("DRBG");
            } finally {
                Security.setProperty("drbg", old);
            }
        }
    }

    private static SecureRandom revive(SecureRandom sr) throws Exception {
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        new ObjectOutputStream(bout).writeObject(sr);
        return (SecureRandom) new ObjectInputStream(
                new ByteArrayInputStream(bout.toByteArray())).readObject();
    }
}