/*

 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. 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.  Oracle designates this

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

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.crypto.provider;

import java.security.Key;

import java.security.PublicKey;

import java.security.PrivateKey;

import java.security.KeyFactory;

import java.security.InvalidKeyException;

import java.security.NoSuchProviderException;

import java.security.NoSuchAlgorithmException;

import java.security.spec.PKCS8EncodedKeySpec;

import java.security.spec.X509EncodedKeySpec;

import java.security.spec.InvalidKeySpecException;

import javax.crypto.Cipher;

import javax.crypto.CipherSpi;

import javax.crypto.SecretKey;

import javax.crypto.IllegalBlockSizeException;

import javax.crypto.BadPaddingException;

import javax.crypto.spec.SecretKeySpec;

/**

 * This class entends the javax.crypto.CipherSpi class with a concrete

 * implementation of the methods for wrapping and unwrapping

 * keys.

 *

 * @author Sharon Liu

 *

 *

 * @see javax.crypto.CipherSpi

 * @see BlowfishCipher

 * @see DESCipher

 * @see PBEWithMD5AndDESCipher

 */

public abstract class CipherWithWrappingSpi extends CipherSpi {

    /**

     * Wrap a key.

     *

     * @param key the key to be wrapped.

     *

     * @return the wrapped key.

     *

     * @exception IllegalBlockSizeException if this cipher is a block

     * cipher, no padding has been requested, and the length of the

     * encoding of the key to be wrapped is not a

     * multiple of the block size.

     *

     * @exception InvalidKeyException if it is impossible or unsafe to

     * wrap the key with this cipher (e.g., a hardware protected key is

     * being passed to a software only cipher).

     */

    protected final byte[] engineWrap(Key key)

        throws IllegalBlockSizeException, InvalidKeyException

    {

        byte[] result = null;

        try {

            byte[] encodedKey = key.getEncoded();

            if ((encodedKey == null) || (encodedKey.length == 0)) {

                throw new InvalidKeyException("Cannot get an encoding of " +

                                              "the key to be wrapped");

            }

            result = engineDoFinal(encodedKey, 0, encodedKey.length);

        } catch (BadPaddingException e) {

            // Should never happen

        }

        return result;

    }

    /**

     * Unwrap a previously wrapped key.

     *

     * @param wrappedKey the key to be unwrapped.

     *

     * @param wrappedKeyAlgorithm the algorithm the wrapped key is for.

     *

     * @param wrappedKeyType the type of the wrapped key.

     * This is one of <code>Cipher.SECRET_KEY</code>,

     * <code>Cipher.PRIVATE_KEY</code>, or <code>Cipher.PUBLIC_KEY</code>.

     *

     * @return the unwrapped key.

     *

     * @exception InvalidKeyException if <code>wrappedKey</code> does not

     * represent a wrapped key, or if the algorithm associated with the

     * wrapped key is different from <code>wrappedKeyAlgorithm</code>

     * and/or its key type is different from <code>wrappedKeyType</code>.

     *

     * @exception NoSuchAlgorithmException if no installed providers

     * can create keys for the <code>wrappedKeyAlgorithm</code>.

     */

    protected final Key engineUnwrap(byte[] wrappedKey,

                                     String wrappedKeyAlgorithm,

                                     int wrappedKeyType)

        throws InvalidKeyException, NoSuchAlgorithmException

    {

        byte[] encodedKey;

        Key result = null;

        try {

            encodedKey = engineDoFinal(wrappedKey, 0,

                                       wrappedKey.length);

        } catch (BadPaddingException ePadding) {

            throw new InvalidKeyException();

        } catch (IllegalBlockSizeException eBlockSize) {

            throw new InvalidKeyException();

        }

        switch (wrappedKeyType) {

        case Cipher.SECRET_KEY:

            result = constructSecretKey(encodedKey,

                                        wrappedKeyAlgorithm);

            break;

        case Cipher.PRIVATE_KEY:

            result = constructPrivateKey(encodedKey,

                                         wrappedKeyAlgorithm);

            break;

        case Cipher.PUBLIC_KEY:

            result = constructPublicKey(encodedKey,

                                        wrappedKeyAlgorithm);

            break;

        }

        return result;

    }

    /**

     * Construct a public key from its encoding.

     *

     * @param encodedKey the encoding of a public key.

     *

     * @param encodedKeyAlgorithm the algorithm the encodedKey is for.

     *

     * @return a public key constructed from the encodedKey.

     */

    private final PublicKey constructPublicKey(byte[] encodedKey,

                                               String encodedKeyAlgorithm)

        throws InvalidKeyException, NoSuchAlgorithmException

    {

        PublicKey key = null;

        try {

            KeyFactory keyFactory =

                KeyFactory.getInstance(encodedKeyAlgorithm,

                    SunJCE.getInstance());

            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(encodedKey);

            key = keyFactory.generatePublic(keySpec);

        } catch (NoSuchAlgorithmException nsae) {

            // Try to see whether there is another

            // provider which supports this algorithm

            try {

                KeyFactory keyFactory =

                    KeyFactory.getInstance(encodedKeyAlgorithm);

                X509EncodedKeySpec keySpec =

                    new X509EncodedKeySpec(encodedKey);

                key = keyFactory.generatePublic(keySpec);

            } catch (NoSuchAlgorithmException nsae2) {

                throw new NoSuchAlgorithmException("No installed providers " +

                                                   "can create keys for the " +

                                                   encodedKeyAlgorithm +

                                                   "algorithm");

            } catch (InvalidKeySpecException ikse2) {

                // Should never happen.

            }

        } catch (InvalidKeySpecException ikse) {

            // Should never happen.

        }

        return key;

    }

    /**

     * Construct a private key from its encoding.

     *

     * @param encodedKey the encoding of a private key.

     *

     * @param encodedKeyAlgorithm the algorithm the wrapped key is for.

     *

     * @return a private key constructed from the encodedKey.

     */

    private final PrivateKey constructPrivateKey(byte[] encodedKey,

                                                 String encodedKeyAlgorithm)

        throws InvalidKeyException, NoSuchAlgorithmException

    {

        PrivateKey key = null;

        try {

            KeyFactory keyFactory =

                KeyFactory.getInstance(encodedKeyAlgorithm,

                    SunJCE.getInstance());

            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encodedKey);

            return keyFactory.generatePrivate(keySpec);

        } catch (NoSuchAlgorithmException nsae) {

            // Try to see whether there is another

            // provider which supports this algorithm

            try {

                KeyFactory keyFactory =

                    KeyFactory.getInstance(encodedKeyAlgorithm);

                PKCS8EncodedKeySpec keySpec =

                    new PKCS8EncodedKeySpec(encodedKey);

                key = keyFactory.generatePrivate(keySpec);

            } catch (NoSuchAlgorithmException nsae2) {

                throw new NoSuchAlgorithmException("No installed providers " +

                                                   "can create keys for the " +

                                                   encodedKeyAlgorithm +

                                                   "algorithm");

            } catch (InvalidKeySpecException ikse2) {

                // Should never happen.

            }

        } catch (InvalidKeySpecException ikse) {

            // Should never happen.

        }

        return key;

    }

    /**

     * Construct a secret key from its encoding.

     *

     * @param encodedKey the encoding of a secret key.

     *

     * @param encodedKeyAlgorithm the algorithm the secret key is for.

     *

     * @return a secret key constructed from the encodedKey.

     */

    private final SecretKey constructSecretKey(byte[] encodedKey,

                                               String encodedKeyAlgorithm)

    {

        return (new SecretKeySpec(encodedKey, encodedKeyAlgorithm));

    }

}