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/*
* Copyright (c) 2005, 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.
*
* 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 6330287 6331386 7044060
* @summary verify that DHKeyPairGenerator returns keys of the expected size
* (modulus and exponent)
* -and-
* DHKeyPairGenerator is using BigInteger.setBit
* @author Andreas Sterbenz
*/
import java.math.BigInteger;
import java.util.Arrays;
import java.security.*;
import javax.crypto.*;
import javax.crypto.interfaces.*;
import javax.crypto.spec.*;
/*
* NOTE: BigInteger's bitlength() doesn't report leading zeros, only
* the number of bits needed to actually represent the number. i.e.
*
* new BigInteger("4").bitLength() = 3
*
* Since the private key x can vary 1 <= x <= p-2, we can't do any
* bitlength-based calculations here. But we can check that p conforms
* as expected.
*
* If not specified, we're currently using an lsize of Math.max(384, psize/2).
*/
public class TestExponentSize {
/*
* Sizes and values for various lengths.
*/
private enum Sizes {
two56(256), three84(384), five12(512), seven68(768), ten24(1024),
twenty48(2048);
private final int intSize;
private final BigInteger bigIntValue;
Sizes(int size) {
intSize = size;
byte [] bits = new byte[intSize/8];
Arrays.fill(bits, (byte)0xff);
bigIntValue = new BigInteger(1, bits);
}
int getIntSize() {
return intSize;
}
BigInteger getBigIntValue() {
return bigIntValue;
}
}
public static void main(String[] args) throws Exception {
KeyPair kp;
KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH", "SunJCE");
// Sun's default uses a default psize of 2048 and
// lsize of (pSize / 2) but at least 384 bits
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.twenty48, Sizes.ten24);
DHPublicKey publicKey = (DHPublicKey)kp.getPublic();
BigInteger p = publicKey.getParams().getP();
BigInteger g = publicKey.getParams().getG();
kpg.initialize(Sizes.ten24.getIntSize());
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.ten24, Sizes.five12);
kpg.initialize(new DHParameterSpec(p, g, Sizes.ten24.getIntSize()));
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.twenty48, Sizes.ten24);
kpg.initialize(new DHParameterSpec(p, g, Sizes.five12.getIntSize()));
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.twenty48, Sizes.five12);
kpg.initialize(new DHParameterSpec(p, g, Sizes.two56.getIntSize()));
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.twenty48, Sizes.two56);
kpg.initialize(Sizes.five12.getIntSize());
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.five12, Sizes.three84);
kpg.initialize(Sizes.seven68.getIntSize());
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.seven68, Sizes.three84);
// test w/ only pSize
kpg.initialize(Sizes.twenty48.getIntSize());
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.twenty48, Sizes.ten24);
publicKey = (DHPublicKey)kp.getPublic();
p = publicKey.getParams().getP();
g = publicKey.getParams().getG();
// test w/ all values specified
kpg.initialize(new DHParameterSpec(p, g, Sizes.five12.getIntSize()));
kp = kpg.generateKeyPair();
checkKeyPair(kp, Sizes.twenty48, Sizes.five12);
System.out.println("OK");
}
private static void checkKeyPair(KeyPair kp, Sizes modulusSize,
Sizes exponentSize) throws Exception {
System.out.println("Checking (" + modulusSize + ", " +
exponentSize + ")");
DHPrivateKey privateKey = (DHPrivateKey)kp.getPrivate();
BigInteger p = privateKey.getParams().getP();
BigInteger x = privateKey.getX();
if (p.bitLength() != modulusSize.getIntSize()) {
throw new Exception("Invalid modulus size: " + p.bitLength());
}
if (x.bitLength() > exponentSize.getIntSize()) {
throw new Exception("X has more bits than expected: " +
x.bitLength());
}
BigInteger pMinus2 =
p.subtract(BigInteger.ONE).subtract(BigInteger.ONE);
if ((x.compareTo(BigInteger.ONE) < 0 ||
(x.compareTo(pMinus2)) > 0)) {
throw new Exception(
"X outside range 1<=x<p-2: x: " + x + " p: " + p);
}
}
}
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