/* * Copyright (c) 1997, 2007, 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * 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. */package com.sun.crypto.provider;import java.math.BigInteger;import java.security.*;import java.security.spec.AlgorithmParameterSpec;import java.security.spec.InvalidParameterSpecException;import javax.crypto.spec.DHParameterSpec;import javax.crypto.spec.DHGenParameterSpec;import sun.security.provider.ParameterCache;/** * This class represents the key pair generator for Diffie-Hellman key pairs. * * <p>This key pair generator may be initialized in two different ways: * * <ul> * <li>By providing the size in bits of the prime modulus - * This will be used to create a prime modulus and base generator, which will * then be used to create the Diffie-Hellman key pair. The default size of the * prime modulus is 1024 bits. * <li>By providing a prime modulus and base generator * </ul> * * @author Jan Luehe * * * @see java.security.KeyPairGenerator */public final class DHKeyPairGenerator extends KeyPairGeneratorSpi { // parameters to use or null if not specified private DHParameterSpec params; // The size in bits of the prime modulus private int pSize; // The size in bits of the random exponent (private value) private int lSize; // The source of randomness private SecureRandom random; public DHKeyPairGenerator() { super(); initialize(1024, null); } /** * Initializes this key pair generator for a certain keysize and source of * randomness. * The keysize is specified as the size in bits of the prime modulus. * * @param keysize the keysize (size of prime modulus) in bits * @param random the source of randomness */ public void initialize(int keysize, SecureRandom random) { if ((keysize < 512) || (keysize > 1024) || (keysize % 64 != 0)) { throw new InvalidParameterException("Keysize must be multiple " + "of 64, and can only range " + "from 512 to 1024 " + "(inclusive)"); } this.pSize = keysize; this.lSize = 0; this.random = random; this.params = null; } /** * Initializes this key pair generator for the specified parameter * set and source of randomness. * * <p>The given parameter set contains the prime modulus, the base * generator, and optionally the requested size in bits of the random * exponent (private value). * * @param params the parameter set used to generate the key pair * @param random the source of randomness * * @exception InvalidAlgorithmParameterException if the given parameters * are inappropriate for this key pair generator */ public void initialize(AlgorithmParameterSpec algParams, SecureRandom random) throws InvalidAlgorithmParameterException { if (!(algParams instanceof DHParameterSpec)){ throw new InvalidAlgorithmParameterException ("Inappropriate parameter type"); } params = (DHParameterSpec)algParams; pSize = params.getP().bitLength(); if ((pSize < 512) || (pSize > 1024) || (pSize % 64 != 0)) { throw new InvalidAlgorithmParameterException ("Prime size must be multiple of 64, and can only range " + "from 512 to 1024 (inclusive)"); } // exponent size is optional, could be 0 lSize = params.getL(); // Require exponentSize < primeSize if ((lSize != 0) && (lSize > pSize)) { throw new InvalidAlgorithmParameterException ("Exponent size must not be larger than modulus size"); } this.random = random; } /** * Generates a key pair. * * @return the new key pair */ public KeyPair generateKeyPair() { if (random == null) { random = SunJCE.RANDOM; } if (params == null) { try { params = ParameterCache.getDHParameterSpec(pSize, random); } catch (GeneralSecurityException e) { // should never happen throw new ProviderException(e); } } BigInteger p = params.getP(); BigInteger g = params.getG(); if (lSize <= 0) { // use an exponent size of (pSize / 2) but at least 384 bits lSize = Math.max(384, pSize >> 1); // if lSize is larger than pSize, limit by pSize lSize = Math.min(lSize, pSize); } BigInteger x; BigInteger pMinus2 = p.subtract(BigInteger.valueOf(2)); // // Handbook of Applied Cryptography: Menezes, et.al. // Repeat if the following does not hold: // 1 <= x <= p-2 // do { // generate random x up to 2^lSize bits long x = new BigInteger(lSize, random); } while ((x.compareTo(BigInteger.ONE) < 0) || ((x.compareTo(pMinus2) > 0))); // calculate public value y BigInteger y = g.modPow(x, p); DHPublicKey pubKey = new DHPublicKey(y, p, g, lSize); DHPrivateKey privKey = new DHPrivateKey(x, p, g, lSize); return new KeyPair(pubKey, privKey); }}
/*
* Copyright (c) 1997, 2007, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*/
package com.sun.crypto.provider;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidParameterSpecException;
import javax.crypto.spec.DHParameterSpec;
import javax.crypto.spec.DHGenParameterSpec;
import sun.security.provider.ParameterCache;
/**
* This class represents the key pair generator for Diffie-Hellman key pairs.
*
* <p>This key pair generator may be initialized in two different ways:
*
* <ul>
* <li>By providing the size in bits of the prime modulus -
* This will be used to create a prime modulus and base generator, which will
* then be used to create the Diffie-Hellman key pair. The default size of the
* prime modulus is 1024 bits.
* <li>By providing a prime modulus and base generator
* </ul>
*
* @author Jan Luehe
*
*
* @see java.security.KeyPairGenerator
*/
public final class DHKeyPairGenerator extends KeyPairGeneratorSpi {
// parameters to use or null if not specified
private DHParameterSpec params;
// The size in bits of the prime modulus
private int pSize;
// The size in bits of the random exponent (private value)
private int lSize;
// The source of randomness
private SecureRandom random;
public DHKeyPairGenerator() {
super();
initialize(1024, null);
}
/**
* Initializes this key pair generator for a certain keysize and source of
* randomness.
* The keysize is specified as the size in bits of the prime modulus.
*
* @param keysize the keysize (size of prime modulus) in bits
* @param random the source of randomness
*/
public void initialize(int keysize, SecureRandom random) {
if ((keysize < 512) || (keysize > 1024) || (keysize % 64 != 0)) {
throw new InvalidParameterException("Keysize must be multiple "
+ "of 64, and can only range "
+ "from 512 to 1024 "
+ "(inclusive)");
}
this.pSize = keysize;
this.lSize = 0;
this.random = random;
this.params = null;
}
/**
* Initializes this key pair generator for the specified parameter
* set and source of randomness.
*
* <p>The given parameter set contains the prime modulus, the base
* generator, and optionally the requested size in bits of the random
* exponent (private value).
*
* @param params the parameter set used to generate the key pair
* @param random the source of randomness
*
* @exception InvalidAlgorithmParameterException if the given parameters
* are inappropriate for this key pair generator
*/
public void initialize(AlgorithmParameterSpec algParams,
SecureRandom random) throws InvalidAlgorithmParameterException {
if (!(algParams instanceof DHParameterSpec)){
throw new InvalidAlgorithmParameterException
("Inappropriate parameter type");
}
params = (DHParameterSpec)algParams;
pSize = params.getP().bitLength();
if ((pSize < 512) || (pSize > 1024) ||
(pSize % 64 != 0)) {
throw new InvalidAlgorithmParameterException
("Prime size must be multiple of 64, and can only range "
+ "from 512 to 1024 (inclusive)");
}
// exponent size is optional, could be 0
lSize = params.getL();
// Require exponentSize < primeSize
if ((lSize != 0) && (lSize > pSize)) {
throw new InvalidAlgorithmParameterException
("Exponent size must not be larger than modulus size");
}
this.random = random;
}
/**
* Generates a key pair.
*
* @return the new key pair
*/
public KeyPair generateKeyPair() {
if (random == null) {
random = SunJCE.RANDOM;
}
if (params == null) {
try {
params = ParameterCache.getDHParameterSpec(pSize, random);
} catch (GeneralSecurityException e) {
// should never happen
throw new ProviderException(e);
}
}
BigInteger p = params.getP();
BigInteger g = params.getG();
if (lSize <= 0) {
// use an exponent size of (pSize / 2) but at least 384 bits
lSize = Math.max(384, pSize >> 1);
// if lSize is larger than pSize, limit by pSize
lSize = Math.min(lSize, pSize);
}
BigInteger x;
BigInteger pMinus2 = p.subtract(BigInteger.valueOf(2));
//
// Handbook of Applied Cryptography: Menezes, et.al.
// Repeat if the following does not hold:
// 1 <= x <= p-2
//
do {
// generate random x up to 2^lSize bits long
x = new BigInteger(lSize, random);
} while ((x.compareTo(BigInteger.ONE) < 0) ||
((x.compareTo(pMinus2) > 0)));
// calculate public value y
BigInteger y = g.modPow(x, p);
DHPublicKey pubKey = new DHPublicKey(y, p, g, lSize);
DHPrivateKey privKey = new DHPrivateKey(x, p, g, lSize);
return new KeyPair(pubKey, privKey);
}
}