/*

 * Copyright 1997-2007 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 com.sun.crypto.provider;

import javax.crypto.SecretKey;

import javax.crypto.SecretKeyFactorySpi;

import javax.crypto.spec.DESKeySpec;

import java.security.InvalidKeyException;

import java.security.spec.KeySpec;

import java.security.spec.InvalidKeySpecException;

/**

 * This class implements the DES key factory of the Sun provider.

 *

 * @author Jan Luehe

 *

 */

public final class DESKeyFactory extends SecretKeyFactorySpi {

    /**

     * Verify the SunJCE provider in the constructor.

     *

     * @exception SecurityException if fails to verify

     * its own integrity

     */

    public DESKeyFactory() {

        if (!SunJCE.verifySelfIntegrity(this.getClass())) {

            throw new SecurityException("The SunJCE provider may have " +

                                        "been tampered.");

        }

    }

    /**

     * Generates a <code>SecretKey</code> object from the provided key

     * specification (key material).

     *

     * @param keySpec the specification (key material) of the secret key

     *

     * @return the secret key

     *

     * @exception InvalidKeySpecException if the given key specification

     * is inappropriate for this key factory to produce a public key.

     */

    protected SecretKey engineGenerateSecret(KeySpec keySpec)

        throws InvalidKeySpecException {

        DESKey desKey = null;

        try {

            if (!(keySpec instanceof DESKeySpec)) {

                throw new InvalidKeySpecException

                    ("Inappropriate key specification");

            }

            else {

                DESKeySpec desKeySpec = (DESKeySpec)keySpec;

                desKey = new DESKey(desKeySpec.getKey());

            }

        } catch (InvalidKeyException e) {

        }

        return desKey;

    }

    /**

     * Returns a specification (key material) of the given key

     * in the requested format.

     *

     * @param key the key

     *

     * @param keySpec the requested format in which the key material shall be

     * returned

     *

     * @return the underlying key specification (key material) in the

     * requested format

     *

     * @exception InvalidKeySpecException if the requested key specification is

     * inappropriate for the given key, or the given key cannot be processed

     * (e.g., the given key has an unrecognized algorithm or format).

     */

    protected KeySpec engineGetKeySpec(SecretKey key, Class keySpec)

        throws InvalidKeySpecException {

        try {

            if ((key instanceof SecretKey)

                && (key.getAlgorithm().equalsIgnoreCase("DES"))

                && (key.getFormat().equalsIgnoreCase("RAW"))) {

                // Check if requested key spec is amongst the valid ones

                if ((keySpec != null) &&

                    DESKeySpec.class.isAssignableFrom(keySpec)) {

                    return new DESKeySpec(key.getEncoded());

                } else {

                    throw new InvalidKeySpecException

                        ("Inappropriate key specification");

                }

            } else {

                throw new InvalidKeySpecException

                    ("Inappropriate key format/algorithm");

            }

        } catch (InvalidKeyException e) {

            throw new InvalidKeySpecException("Secret key has wrong size");

        }

    }

    /**

     * Translates a <code>SecretKey</code> object, whose provider may be

     * unknown or potentially untrusted, into a corresponding

     * <code>SecretKey</code> object of this key factory.

     *

     * @param key the key whose provider is unknown or untrusted

     *

     * @return the translated key

     *

     * @exception InvalidKeyException if the given key cannot be processed by

     * this key factory.

     */

    protected SecretKey engineTranslateKey(SecretKey key)

        throws InvalidKeyException {

        try {

            if ((key != null) &&

                (key.getAlgorithm().equalsIgnoreCase("DES")) &&

                (key.getFormat().equalsIgnoreCase("RAW"))) {

                // Check if key originates from this factory

                if (key instanceof com.sun.crypto.provider.DESKey) {

                    return key;

                }

                // Convert key to spec

                DESKeySpec desKeySpec

                    = (DESKeySpec)engineGetKeySpec(key, DESKeySpec.class);

                // Create key from spec, and return it

                return engineGenerateSecret(desKeySpec);

            } else {

                throw new InvalidKeyException

                    ("Inappropriate key format/algorithm");

            }

        } catch (InvalidKeySpecException e) {

            throw new InvalidKeyException("Cannot translate key");

        }

    }

}