test/jdk/sun/security/provider/SecureRandom/SHA1PRNGReseed.java

/*
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 * 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.
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import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.SecureRandom;

/**
 * @test
 * @bug 8154523
 * @summary SHA1PRNG output should change after setSeed
 */
public class SHA1PRNGReseed {

    public static void main(String[] args) throws Exception {
        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
        sr.setSeed(0);
        sr.nextInt();

        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        new ObjectOutputStream(bout).writeObject(sr);

        SecureRandom sr2 = (SecureRandom) new ObjectInputStream(
                new ByteArrayInputStream(bout.toByteArray())).readObject();

        int i1 = sr.nextInt();
        sr2.setSeed(1);
        int i2 = sr2.nextInt();

        if (i1 == i2) {
            throw new Exception("output should not be the same");
        }
    }
}