| /* SRPPublicKey.java -- |
| Copyright (C) 2003, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.javax.crypto.key.srp6; |
| |
| import gnu.java.security.Registry; |
| import gnu.java.security.key.IKeyPairCodec; |
| |
| import java.math.BigInteger; |
| import java.security.PublicKey; |
| |
| /** |
| * A representation of an SRP ephemeral public key. |
| * <p> |
| * Reference: |
| * <ol> |
| * <li><a href="http://srp.stanford.edu/design.html">SRP Protocol Design</a><br> |
| * Thomas J. Wu.</li> |
| * </ol> |
| */ |
| public class SRPPublicKey |
| extends SRPKey |
| implements PublicKey |
| { |
| /** |
| * The public exponent for either the server or the client engaged in the SRP |
| * protocol exchange. |
| */ |
| private final BigInteger Y; |
| |
| /** |
| * Public constructor for use from outside this package. |
| * |
| * @param N the public shared modulus. |
| * @param g the generator. |
| * @param Y the public exponent of the ephemeral key. |
| */ |
| public SRPPublicKey(BigInteger N, BigInteger g, BigInteger Y) |
| { |
| super(N, g); |
| |
| SRPAlgorithm.checkParams(N, g); |
| this.Y = Y; |
| } |
| |
| /** |
| * Default constructor. Assumes that N and g are already validated. |
| * |
| * @param params an array of 3 values representing N, g and Y; the latter |
| * being the client's or server's public exponent. |
| */ |
| SRPPublicKey(BigInteger[] params) |
| { |
| super(params[0], params[1]); |
| |
| this.Y = params[2]; |
| } |
| |
| /** |
| * A class method that takes the output of the <code>encodePublicKey()</code> |
| * method of an SRP keypair codec object (an instance implementing |
| * {@link IKeyPairCodec} for SRP keys, and re-constructs an instance of this |
| * object. |
| * |
| * @param k the contents of a previously encoded instance of this object. |
| * @throws ArrayIndexOutOfBoundsException if there is not enough bytes, in |
| * <code>k</code>, to represent a valid encoding of an instance |
| * of this object. |
| * @throws IllegalArgumentException if the byte sequence does not represent a |
| * valid encoding of an instance of this object. |
| */ |
| public static SRPPublicKey valueOf(byte[] k) |
| { |
| // check magic... |
| // we should parse here enough bytes to know which codec to use, and |
| // direct the byte array to the appropriate codec. since we only have one |
| // codec, we could have immediately tried it; nevertheless since testing |
| // one byte is cheaper than instatiating a codec that will fail we test |
| // the first byte before we carry on. |
| if (k[0] == Registry.MAGIC_RAW_SRP_PUBLIC_KEY[0]) |
| { |
| // it's likely to be in raw format. get a raw codec and hand it over |
| IKeyPairCodec codec = new SRPKeyPairRawCodec(); |
| return (SRPPublicKey) codec.decodePublicKey(k); |
| } |
| throw new IllegalArgumentException("magic"); |
| } |
| |
| /** |
| * Returns the public exponent of the key as a {@link BigInteger}. |
| * |
| * @return the public exponent of the key as a {@link BigInteger}. |
| */ |
| public BigInteger getY() |
| { |
| return Y; |
| } |
| |
| /** |
| * Returns the encoded form of this public key according to the designated |
| * format. |
| * |
| * @param format the desired format identifier of the resulting encoding. |
| * @return the byte sequence encoding this key according to the designated |
| * format. |
| * @throws IllegalArgumentException if the format is not supported. |
| */ |
| public byte[] getEncoded(int format) |
| { |
| byte[] result; |
| switch (format) |
| { |
| case IKeyPairCodec.RAW_FORMAT: |
| result = new SRPKeyPairRawCodec().encodePublicKey(this); |
| break; |
| default: |
| throw new IllegalArgumentException("format"); |
| } |
| return result; |
| } |
| |
| /** |
| * Returns <code>true</code> if the designated object is an instance of |
| * <code>SRPPublicKey</code>and has the same SRP parameter values as this |
| * one. |
| * |
| * @param obj the other non-null SRP key to compare to. |
| * @return <code>true</code> if the designated object is of the same type |
| * and value as this one. |
| */ |
| public boolean equals(Object obj) |
| { |
| if (obj == null) |
| return false; |
| if (! (obj instanceof SRPPublicKey)) |
| return false; |
| SRPPublicKey that = (SRPPublicKey) obj; |
| return super.equals(that) && Y.equals(that.getY()); |
| } |
| } |