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 * Copyright (c) 2016, 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.
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/**
 * @test
 * @bug 8072452
 * @summary Support DHE sizes up to 8192-bits and DSA sizes up to 3072-bits
 * @run main/timeout=300 SupportedDHParamGens 512
 * @run main/timeout=300 SupportedDHParamGens 768
 * @run main/timeout=300 SupportedDHParamGens 832
 * @run main/timeout=300 SupportedDHParamGens 1024
 * @run main/timeout=600 SupportedDHParamGens 2048
 * @run main/timeout=700 SupportedDHParamGens 3072
 */

import java.math.BigInteger;

import java.security.*;
import javax.crypto.*;
import javax.crypto.interfaces.*;
import javax.crypto.spec.*;

public class SupportedDHParamGens {

    public static void main(String[] args) throws Exception {
        int primeSize = Integer.valueOf(args[0]).intValue();

        System.out.println("Checking " + primeSize + " ...");
        AlgorithmParameterGenerator apg =
                AlgorithmParameterGenerator.getInstance("DH", "SunJCE");
        apg.init(primeSize);
        AlgorithmParameters ap = apg.generateParameters();
        DHParameterSpec spec = ap.getParameterSpec(DHParameterSpec.class);

        KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH", "SunJCE");
        kpg.initialize(spec);
        KeyPair kp = kpg.generateKeyPair();
        checkKeyPair(kp, primeSize);
    }

    private static void checkKeyPair(KeyPair kp, int pSize) throws Exception {

        DHPrivateKey privateKey = (DHPrivateKey)kp.getPrivate();
        BigInteger p = privateKey.getParams().getP();
        if (p.bitLength() != pSize) {
            throw new Exception(
                "Invalid modulus size: " + p.bitLength() + "/" + pSize);
        }

        if (!p.isProbablePrime(128)) {
            throw new Exception("Good luck, the modulus is composite!");
        }

        DHPublicKey publicKey = (DHPublicKey)kp.getPublic();
        p = publicKey.getParams().getP();
        if (p.bitLength() != pSize) {
            throw new Exception(
                "Invalid modulus size: " + p.bitLength() + "/" + pSize);
        }

        BigInteger leftOpen = BigInteger.ONE;
        BigInteger rightOpen = p.subtract(BigInteger.ONE);

        BigInteger x = privateKey.getX();
        if ((x.compareTo(leftOpen) <= 0) ||
                (x.compareTo(rightOpen) >= 0)) {
            throw new Exception(
                "X outside range [2, p - 2]:  x: " + x + " p: " + p);
        }

        BigInteger y = publicKey.getY();
        if ((y.compareTo(leftOpen) <= 0) ||
                (y.compareTo(rightOpen) >= 0)) {
            throw new Exception(
                "Y outside range [2, p - 2]:  x: " + x + " p: " + p);
        }
    }
}