/*

 * Copyright (c) 1997, 2018, 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

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 */

package com.sun.crypto.provider;

import java.security.MessageDigest;

import java.security.KeyRep;

import java.security.spec.InvalidKeySpecException;

import java.util.Arrays;

import java.util.Locale;

import javax.crypto.SecretKey;

import javax.crypto.spec.PBEKeySpec;

/**

 * This class represents a PBE key.

 *

 * @author Jan Luehe

 *

 */

final class PBEKey implements SecretKey {

    static final long serialVersionUID = -2234768909660948176L;

    private byte[] key;

    private String type;

    /**

     * Creates a PBE key from a given PBE key specification.

     *

     * @param key the given PBE key specification

     */

    PBEKey(PBEKeySpec keySpec, String keytype) throws InvalidKeySpecException {

        char[] passwd = keySpec.getPassword();

        if (passwd == null) {

            // Should allow an empty password.

            passwd = new char[0];

        }

        // Accept "\0" to signify "zero-length password with no terminator".

        if (!(passwd.length == 1 && passwd[0] == 0)) {

            for (int i=0; i<passwd.length; i++) {

                if ((passwd[i] < '\u0020') || (passwd[i] > '\u007E')) {

                    throw new InvalidKeySpecException("Password is not ASCII");

                }

            }

        }

        this.key = new byte[passwd.length];

        for (int i=0; i<passwd.length; i++)

            this.key[i] = (byte) (passwd[i] & 0x7f);

        Arrays.fill(passwd, '\0');

        type = keytype;

    }

    public synchronized byte[] getEncoded() {

        return this.key.clone();

    }

    public String getAlgorithm() {

        return type;

    }

    public String getFormat() {

        return "RAW";

    }

    /**

     * Calculates a hash code value for the object.

     * Objects that are equal will also have the same hashcode.

     */

    public int hashCode() {

        int retval = 0;

        for (int i = 1; i < this.key.length; i++) {

            retval += this.key[i] * i;

        }

        return(retval ^= getAlgorithm().toLowerCase(Locale.ENGLISH).hashCode());

    }

    public boolean equals(Object obj) {

        if (obj == this)

            return true;

        if (!(obj instanceof SecretKey))

            return false;

        SecretKey that = (SecretKey)obj;

        if (!(that.getAlgorithm().equalsIgnoreCase(type)))

            return false;

        byte[] thatEncoded = that.getEncoded();

        boolean ret = MessageDigest.isEqual(this.key, thatEncoded);

        Arrays.fill(thatEncoded, (byte)0x00);

        return ret;

    }

    /**

     * Clears the internal copy of the key.

     *

     */

    @Override

    public void destroy() {

        if (key != null) {

            Arrays.fill(key, (byte)0x00);

            key = null;

        }

    }

    /**

     * readObject is called to restore the state of this key from

     * a stream.

     */

    private void readObject(java.io.ObjectInputStream s)

         throws java.io.IOException, ClassNotFoundException

    {

        s.defaultReadObject();

        key = key.clone();

    }

    /**

     * Replace the PBE key to be serialized.

     *

     * @return the standard KeyRep object to be serialized

     *

     * @throws java.io.ObjectStreamException if a new object representing

     * this PBE key could not be created

     */

    private Object writeReplace() throws java.io.ObjectStreamException {

        return new KeyRep(KeyRep.Type.SECRET,

                        getAlgorithm(),

                        getFormat(),

                        getEncoded());

    }

    /**

     * Ensures that the password bytes of this key are

     * set to zero when there are no more references to it.

     */

    protected void finalize() throws Throwable {

        try {

            synchronized (this) {

                if (this.key != null) {

                    java.util.Arrays.fill(this.key, (byte)0x00);

                    this.key = null;

                }

            }

        } finally {

            super.finalize();

        }

    }

}