/*

 * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.security;

import java.io.*;

import java.security.spec.PKCS8EncodedKeySpec;

import java.security.spec.X509EncodedKeySpec;

import java.security.spec.InvalidKeySpecException;

import javax.crypto.SecretKeyFactory;

import javax.crypto.spec.SecretKeySpec;

/**

 * Standardized representation for serialized Key objects.

 *

 * <p>

 *

 * Note that a serialized Key may contain sensitive information

 * which should not be exposed in untrusted environments.  See the

 * <a href="../../../platform/serialization/spec/security.html">

 * Security Appendix</a>

 * of the Serialization Specification for more information.

 *

 * @see Key

 * @see KeyFactory

 * @see javax.crypto.spec.SecretKeySpec

 * @see java.security.spec.X509EncodedKeySpec

 * @see java.security.spec.PKCS8EncodedKeySpec

 *

 * @since 1.5

 */

public class KeyRep implements Serializable {

    private static final long serialVersionUID = -4757683898830641853L;

    /**

     * Key type.

     *

     * @since 1.5

     */

    public static enum Type {

        /** Type for secret keys. */

        SECRET,

        /** Type for public keys. */

        PUBLIC,

        /** Type for private keys. */

        PRIVATE,

    }

    private static final String PKCS8 = "PKCS#8";

    private static final String X509 = "X.509";

    private static final String RAW = "RAW";

    /**

     * Either one of Type.SECRET, Type.PUBLIC, or Type.PRIVATE

     *

     * @serial

     */

    private Type type;

    /**

     * The Key algorithm

     *

     * @serial

     */

    private String algorithm;

    /**

     * The Key encoding format

     *

     * @serial

     */

    private String format;

    /**

     * The encoded Key bytes

     *

     * @serial

     */

    private byte[] encoded;

    /**

     * Construct the alternate Key class.

     *

     * <p>

     *

     * @param type either one of Type.SECRET, Type.PUBLIC, or Type.PRIVATE

     * @param algorithm the algorithm returned from

     *          <code>Key.getAlgorithm()</code>

     * @param format the encoding format returned from

     *          <code>Key.getFormat()</code>

     * @param encoded the encoded bytes returned from

     *          <code>Key.getEncoded()</code>

     *

     * @exception NullPointerException

     *          if type is <code>null</code>,

     *          if algorithm is <code>null</code>,

     *          if format is <code>null</code>,

     *          or if encoded is <code>null</code>

     */

    public KeyRep(Type type, String algorithm,

                String format, byte[] encoded) {

        if (type == null || algorithm == null ||

            format == null || encoded == null) {

            throw new NullPointerException("invalid null input(s)");

        }

        this.type = type;

        this.algorithm = algorithm;

        this.format = format.toUpperCase();

        this.encoded = encoded.clone();

    }

    /**

     * Resolve the Key object.

     *

     * <p> This method supports three Type/format combinations:

     * <ul>

     * <li> Type.SECRET/"RAW" - returns a SecretKeySpec object

     * constructed using encoded key bytes and algorithm

     * <li> Type.PUBLIC/"X.509" - gets a KeyFactory instance for

     * the key algorithm, constructs an X509EncodedKeySpec with the

     * encoded key bytes, and generates a public key from the spec

     * <li> Type.PRIVATE/"PKCS#8" - gets a KeyFactory instance for

     * the key algorithm, constructs a PKCS8EncodedKeySpec with the

     * encoded key bytes, and generates a private key from the spec

     * </ul>

     *

     * <p>

     *

     * @return the resolved Key object

     *

     * @exception ObjectStreamException if the Type/format

     *  combination is unrecognized, if the algorithm, key format, or

     *  encoded key bytes are unrecognized/invalid, of if the

     *  resolution of the key fails for any reason

     */

    protected Object readResolve() throws ObjectStreamException {

        try {

            if (type == Type.SECRET && RAW.equals(format)) {

                return new SecretKeySpec(encoded, algorithm);

            } else if (type == Type.PUBLIC && X509.equals(format)) {

                KeyFactory f = KeyFactory.getInstance(algorithm);

                return f.generatePublic(new X509EncodedKeySpec(encoded));

            } else if (type == Type.PRIVATE && PKCS8.equals(format)) {

                KeyFactory f = KeyFactory.getInstance(algorithm);

                return f.generatePrivate(new PKCS8EncodedKeySpec(encoded));

            } else {

                throw new NotSerializableException

                        ("unrecognized type/format combination: " +

                        type + "/" + format);

            }

        } catch (NotSerializableException nse) {

            throw nse;

        } catch (Exception e) {

            NotSerializableException nse = new NotSerializableException

                                        ("java.security.Key: " +

                                        "[" + type + "] " +

                                        "[" + algorithm + "] " +

                                        "[" + format + "]");

            nse.initCause(e);

            throw nse;

        }

    }

}