TestInitSignWithMyOwnRandom.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/**
 * @test
 * @bug 4716321
 * @summary Ensure the random source supplied in
 * Signature.initSign(PrivateKey, SecureRandom) is used.
 */
import java.security.*;

public class TestInitSignWithMyOwnRandom {

    public static void main(String[] argv) throws Exception {
        // any signature implementation will do as long as
        // it needs a random source
        Provider p = Security.getProvider("SUN");
        KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA", p);
        kpg.initialize(512);
        KeyPair kp = kpg.generateKeyPair();
        TestRandomSource rand = new TestRandomSource();
        Signature sig = Signature.getInstance("DSA", p);
        sig.initSign(kp.getPrivate(), rand);
        sig.update(new byte[20]);
        sig.sign();
        if (rand.isUsed()) {
            System.out.println("Custom random source is used.");
        } else {
            throw new Exception("Custom random source is not used");
        }
    }
}

class TestRandomSource extends SecureRandom {

    int count = 0;

    @Override
    public void nextBytes(byte[] rs) {
        count++;
    }

    public boolean isUsed() {
        return (count != 0);
    }
}