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1: /* GnuDHPublicKey.java -- 2: Copyright (C) 2003, 2006 Free Software Foundation, Inc. 3: 4: This file is a 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 of the License, or (at 9: your option) 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; if not, write to the Free Software 18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 19: 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.javax.crypto.key.dh; 40: 41: import gnu.java.security.Registry; 42: import gnu.java.security.action.GetPropertyAction; 43: import gnu.java.security.key.IKeyPairCodec; 44: 45: import java.math.BigInteger; 46: import java.security.AccessController; 47: 48: import javax.crypto.interfaces.DHPublicKey; 49: 50: /** 51: * An implementation of the Diffie-Hellman public key. 52: * <p> 53: * Reference: 54: * <ol> 55: * <li><a href="http://www.ietf.org/rfc/rfc2631.txt">Diffie-Hellman Key 56: * Agreement Method</a><br> 57: * Eric Rescorla.</li> 58: * </ol> 59: */ 60: public class GnuDHPublicKey 61: extends GnuDHKey 62: implements DHPublicKey 63: { 64: private BigInteger y; 65: /** String representation of this key. Cached for speed. */ 66: private transient String str; 67: 68: /** 69: * Convenience constructor. Calls the constructor with five arguments passing 70: * {@link Registry#RAW_ENCODING_ID} as the value of its first argument. 71: * 72: * @param q a prime divisor of p-1. 73: * @param p the public prime. 74: * @param g the generator of the group. 75: * @param y the public value y. 76: */ 77: public GnuDHPublicKey(BigInteger q, BigInteger p, BigInteger g, BigInteger y) 78: { 79: this(Registry.RAW_ENCODING_ID, q, p, g, y); 80: } 81: 82: /** 83: * Constructs a new instance of <code>GnuDHPublicKey</code> given the 84: * designated parameters. 85: * 86: * @param preferredFormat the identifier of the encoding format to use by 87: * default when externalizing the key. 88: * @param q a prime divisor of p-1. 89: * @param p the public prime. 90: * @param g the generator of the group. 91: * @param y the public value y. 92: */ 93: public GnuDHPublicKey(int preferredFormat, BigInteger q, BigInteger p, 94: BigInteger g, BigInteger y) 95: { 96: super(preferredFormat == Registry.ASN1_ENCODING_ID ? Registry.X509_ENCODING_ID 97: : preferredFormat, 98: q, p, g); 99: this.y = y; 100: } 101: 102: /** 103: * A class method that takes the output of the <code>encodePublicKey()</code> 104: * method of a DH keypair codec object (an instance implementing 105: * {@link IKeyPairCodec} for DSS keys, and re-constructs an instance of this 106: * object. 107: * 108: * @param k the contents of a previously encoded instance of this object. 109: * @exception ArrayIndexOutOfBoundsException if there is not enough bytes, in 110: * <code>k</code>, to represent a valid encoding of an 111: * instance of this object. 112: * @exception IllegalArgumentException if the byte sequence does not represent 113: * a valid encoding of an instance of this object. 114: */ 115: public static GnuDHPublicKey valueOf(byte[] k) 116: { 117: // try RAW codec 118: if (k[0] == Registry.MAGIC_RAW_DH_PUBLIC_KEY[0]) 119: try 120: { 121: return (GnuDHPublicKey) new DHKeyPairRawCodec().decodePublicKey(k); 122: } 123: catch (IllegalArgumentException ignored) 124: { 125: } 126: // try X.509 codec 127: return (GnuDHPublicKey) new DHKeyPairX509Codec().decodePublicKey(k); 128: } 129: 130: public BigInteger getY() 131: { 132: return y; 133: } 134: 135: /** 136: * Returns the encoded form of this public key according to the designated 137: * format. 138: * 139: * @param format the desired format identifier of the resulting encoding. 140: * @return the byte sequence encoding this key according to the designated 141: * format. 142: * @exception IllegalArgumentException if the format is not supported. 143: */ 144: public byte[] getEncoded(int format) 145: { 146: byte[] result; 147: switch (format) 148: { 149: case IKeyPairCodec.RAW_FORMAT: 150: result = new DHKeyPairRawCodec().encodePublicKey(this); 151: break; 152: case IKeyPairCodec.X509_FORMAT: 153: result = new DHKeyPairX509Codec().encodePublicKey(this); 154: break; 155: default: 156: throw new IllegalArgumentException("Unsupported encoding format: " 157: + format); 158: } 159: return result; 160: } 161: 162: /** 163: * Returns <code>true</code> if the designated object is an instance of 164: * {@link DHPublicKey} and has the same parameter values as this one. 165: * 166: * @param obj the other non-null DH key to compare to. 167: * @return <code>true</code> if the designated object is of the same type 168: * and value as this one. 169: */ 170: public boolean equals(Object obj) 171: { 172: if (obj == null) 173: return false; 174: 175: if (! (obj instanceof DHPublicKey)) 176: return false; 177: 178: DHPublicKey that = (DHPublicKey) obj; 179: return super.equals(that) && y.equals(that.getY()); 180: } 181: 182: public String toString() 183: { 184: if (str == null) 185: { 186: String ls = (String) AccessController.doPrivileged 187: (new GetPropertyAction("line.separator")); 188: str = new StringBuilder(this.getClass().getName()).append("(") 189: .append(super.toString()).append(",").append(ls) 190: .append("y=0x").append(y.toString(16)).append(ls) 191: .append(")") 192: .toString(); 193: } 194: return str; 195: } 196: }