package gnu.crypto.key.rsa;
// ----------------------------------------------------------------------------
// $Id: GnuRSAPublicKey.java,v 1.3 2005/10/06 04:24:16 rsdio Exp $
//
// Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto 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, or (at your option)
// any later version.
//
// GNU Crypto 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 this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, 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
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// 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.
// ----------------------------------------------------------------------------
import gnu.crypto.Registry;
import gnu.crypto.key.IKeyPairCodec;
import java.math.BigInteger;
import java.security.PublicKey;
import java.security.interfaces.RSAPublicKey;
/**
* <p>An object that encapsulates an RSA public key.</p>
*
* <p>References:</p>
* <ol>
* <li><a href="http://www.cosic.esat.kuleuven.ac.be/nessie/workshop/submissions/rsa-pss.zip">
* RSA-PSS Signature Scheme with Appendix, part B.</a><br>
* Primitive specification and supporting documentation.<br>
* Jakob Jonsson and Burt Kaliski.</li>
* </ol>
*
* @version $Revision: 1.3 $
*/
public class GnuRSAPublicKey extends GnuRSAKey implements PublicKey, RSAPublicKey {
// Constants and variables
// -------------------------------------------------------------------------
/** The public exponent of an RSA public key. */
// private final BigInteger e;
// Constructor(s)
// -------------------------------------------------------------------------
/**
* <p>Trivial constructor.</p>
*
* @param n the modulus.
* @param e the public exponent.
*/
public GnuRSAPublicKey(final BigInteger n, final BigInteger e) {
// super(n);
super(n, e);
//
// this.e = e;
}
// Class methods
// -------------------------------------------------------------------------
/**
* <p>A class method that takes the output of the <code>encodePublicKey()</code>
* method of an RSA keypair codec object (an instance implementing
* {@link gnu.crypto.key.IKeyPairCodec} for RSA 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 GnuRSAPublicKey valueOf(final 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_RSA_PUBLIC_KEY[0]) {
// it's likely to be in raw format. get a raw codec and hand it over
final IKeyPairCodec codec = new RSAKeyPairRawCodec();
return (GnuRSAPublicKey) codec.decodePublicKey(k);
} else {
throw new IllegalArgumentException("magic");
}
}
// Instance methods
// -------------------------------------------------------------------------
// java.security.interfaces.RSAPublicKey interface implementation ----------
// public BigInteger getPublicExponent() {
// return e;
// }
// 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.
* @see RSAKeyPairRawCodec
*/
public byte[] getEncoded(final int format) {
final byte[] result;
switch (format) {
case IKeyPairCodec.RAW_FORMAT:
result = new RSAKeyPairRawCodec().encodePublicKey(this);
break;
default:
throw new IllegalArgumentException("format");
}
return result;
}
/**
* <p>Returns <code>true</code> if the designated object is an instance of
* this class and has the same RSA parameter values as this one.</p>
*
* @param obj the other non-null RSA 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(final Object obj) {
if (obj == null) {
return false;
}
if (!(obj instanceof RSAPublicKey)) {
return false;
}
final RSAPublicKey that = (RSAPublicKey) obj;
// return super.equals(that) && e.equals(that.getPublicExponent());
return super.equals(that)
&& getPublicExponent().equals(that.getPublicExponent());
}
}