/*

 * Copyright (c) 1999, 2007, 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

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 */

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.SecretKey;

import javax.crypto.Cipher;

import javax.crypto.spec.SecretKeySpec;

/**

 * This class is a helper class which construct key objects

 * from encoded keys.

 *

 * @author Sharon Liu

 *

 */

final class ConstructKeys {

    /**

     * 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 static final PublicKey constructPublicKey(byte[] encodedKey,

                                              String encodedKeyAlgorithm)

        throws InvalidKeyException, NoSuchAlgorithmException

    {

        PublicKey key = null;

        try {

            KeyFactory keyFactory =

                KeyFactory.getInstance(encodedKeyAlgorithm, "SunJCE");

            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) {

                InvalidKeyException ike =

                    new InvalidKeyException("Cannot construct public key");

                ike.initCause(ikse2);

                throw ike;

            }

        } catch (InvalidKeySpecException ikse) {

            InvalidKeyException ike =

                new InvalidKeyException("Cannot construct public key");

            ike.initCause(ikse);

            throw ike;

        } catch (NoSuchProviderException nspe) {

            // 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 static final PrivateKey constructPrivateKey(byte[] encodedKey,

                                                String encodedKeyAlgorithm)

        throws InvalidKeyException, NoSuchAlgorithmException

    {

        PrivateKey key = null;

        try {

            KeyFactory keyFactory =

                KeyFactory.getInstance(encodedKeyAlgorithm, "SunJCE");

            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) {

                InvalidKeyException ike =

                    new InvalidKeyException("Cannot construct private key");

                ike.initCause(ikse2);

                throw ike;

            }

        } catch (InvalidKeySpecException ikse) {

            InvalidKeyException ike =

                new InvalidKeyException("Cannot construct private key");

            ike.initCause(ikse);

            throw ike;

        } catch (NoSuchProviderException nspe) {

            // 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 static final SecretKey constructSecretKey(byte[] encodedKey,

                                              String encodedKeyAlgorithm)

    {

        return (new SecretKeySpec(encodedKey, encodedKeyAlgorithm));

    }

    static final Key constructKey(byte[] encoding, String keyAlgorithm,

                                  int keyType)

        throws InvalidKeyException, NoSuchAlgorithmException {

        Key result = null;

        switch (keyType) {

        case Cipher.SECRET_KEY:

            result = ConstructKeys.constructSecretKey(encoding,

                                                      keyAlgorithm);

            break;

        case Cipher.PRIVATE_KEY:

            result = ConstructKeys.constructPrivateKey(encoding,

                                                       keyAlgorithm);

            break;

        case Cipher.PUBLIC_KEY:

            result = ConstructKeys.constructPublicKey(encoding,

                                                      keyAlgorithm);

            break;

        }

        return result;

    }

}