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Diffstat (limited to 'gnu/javax/crypto/key/srp6/SRPPublicKey.java')
-rw-r--r-- | gnu/javax/crypto/key/srp6/SRPPublicKey.java | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/gnu/javax/crypto/key/srp6/SRPPublicKey.java b/gnu/javax/crypto/key/srp6/SRPPublicKey.java new file mode 100644 index 000000000..7283fd3da --- /dev/null +++ b/gnu/javax/crypto/key/srp6/SRPPublicKey.java @@ -0,0 +1,194 @@ +/* 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; + +/** + * <p>A representation of an SRP ephemeral public key.</p> + * + * <p>Reference:</p> + * <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 +{ + + // Constants and variables + // ------------------------------------------------------------------------- + + /** + * The public exponent for either the server or the client engaged in the + * SRP protocol exchange. + */ + private final BigInteger Y; + + // Constructor(s) + // ------------------------------------------------------------------------- + + /** + * <p>Public constructor for use from outside this package.</p> + * + * @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; + } + + /** + * <p>Default constructor. Assumes that N and g are already validated.</p> + * + * @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]; + } + + // Class methods + // ------------------------------------------------------------------------- + + /** + * <p>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.</p> + * + * @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); + } + else + { + throw new IllegalArgumentException("magic"); + } + } + + // Instance methods + // ------------------------------------------------------------------------- + + /** + * <p>Returns the public exponent of the key as a {@link BigInteger}.</p> + * + * @return the public exponent of the key as a {@link BigInteger}. + */ + public BigInteger getY() + { + return Y; + } + + // Other instance methods -------------------------------------------------- + + /** + * <p>Returns the encoded form of this public key according to the designated + * format.</p> + * + * @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; + } + + /** + * <p>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. + * </p> + * + * @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()); + } +} |