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1: /* DiffieHellmanKeyPairGeneratorImpl.java -- 2: Copyright (C) 2005 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package gnu.java.security.provider; 40: 41: import gnu.javax.crypto.GnuDHPrivateKey; 42: 43: import java.math.BigInteger; 44: 45: import java.security.KeyPair; 46: import java.security.KeyPairGeneratorSpi; 47: import java.security.SecureRandom; 48: import java.security.spec.AlgorithmParameterSpec; 49: 50: import javax.crypto.spec.DHParameterSpec; 51: 52: public class DiffieHellmanKeyPairGeneratorImpl extends KeyPairGeneratorSpi 53: { 54: private SecureRandom random; 55: private DHParameterSpec params; 56: 57: public KeyPair generateKeyPair () 58: { 59: if (params == null || random == null) 60: throw new IllegalStateException ("not initialized"); 61: byte[] buf = new byte[(params.getP ().bitLength() >>> 3)]; 62: random.nextBytes (buf); 63: BigInteger x = new BigInteger (1, buf); 64: BigInteger y = params.getG ().modPow (x, params.getP ()); 65: GnuDHPublicKey pub = new GnuDHPublicKey (params, y, null); 66: GnuDHPrivateKey priv = new GnuDHPrivateKey (x, params); 67: 68: return new KeyPair (pub, priv); 69: } 70: 71: public void initialize (final int keysize, final SecureRandom random) 72: { 73: throw new UnsupportedOperationException ("key generation without parameters not supported"); 74: } 75: 76: public void initialize (final AlgorithmParameterSpec params, 77: final SecureRandom random) 78: { 79: if (!(params instanceof DHParameterSpec)) 80: throw new IllegalArgumentException ("expecting Diffie-Hellman parameters"); 81: this.params = (DHParameterSpec) params; 82: this.random = random; 83: if (this.random == null) 84: this.random = new SecureRandom (); 85: } 86: }