/*

 * Copyright (c) 1996, 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 sun.security.provider;

import java.util.*;

import java.io.*;

import java.math.BigInteger;

import java.security.InvalidKeyException;

import java.security.ProviderException;

import java.security.AlgorithmParameters;

import java.security.spec.DSAParameterSpec;

import java.security.spec.InvalidParameterSpecException;

import java.security.interfaces.DSAParams;

import sun.security.x509.AlgIdDSA;

import sun.security.pkcs.PKCS8Key;

import sun.security.util.Debug;

import sun.security.util.DerValue;

import sun.security.util.DerInputStream;

import sun.security.util.DerOutputStream;

/**

 * A PKCS#8 private key for the Digital Signature Algorithm.

 *

 * @author Benjamin Renaud

 *

 *

 * @see DSAPublicKey

 * @see AlgIdDSA

 * @see DSA

 */

public final class DSAPrivateKey extends PKCS8Key

implements java.security.interfaces.DSAPrivateKey, Serializable {

    /** use serialVersionUID from JDK 1.1. for interoperability */

    private static final long serialVersionUID = -3244453684193605938L;

    /* the private key */

    private BigInteger x;

    /*

     * Keep this constructor for backwards compatibility with JDK1.1.

     */

    public DSAPrivateKey() {

    }

    /**

     * Make a DSA private key out of a private key and three parameters.

     */

    public DSAPrivateKey(BigInteger x, BigInteger p,

                         BigInteger q, BigInteger g)

    throws InvalidKeyException {

        this.x = x;

        algid = new AlgIdDSA(p, q, g);

        try {

            key = new DerValue(DerValue.tag_Integer,

                               x.toByteArray()).toByteArray();

            encode();

        } catch (IOException e) {

            InvalidKeyException ike = new InvalidKeyException(

                "could not DER encode x: " + e.getMessage());

            ike.initCause(e);

            throw ike;

        }

    }

    /**

     * Make a DSA private key from its DER encoding (PKCS #8).

     */

    public DSAPrivateKey(byte[] encoded) throws InvalidKeyException {

        clearOldKey();

        decode(encoded);

    }

    /**

     * Returns the DSA parameters associated with this key, or null if the

     * parameters could not be parsed.

     */

    public DSAParams getParams() {

        try {

            if (algid instanceof DSAParams) {

                return (DSAParams)algid;

            } else {

                DSAParameterSpec paramSpec;

                AlgorithmParameters algParams = algid.getParameters();

                if (algParams == null) {

                    return null;

                }

                paramSpec = algParams.getParameterSpec(DSAParameterSpec.class);

                return (DSAParams)paramSpec;

            }

        } catch (InvalidParameterSpecException e) {

            return null;

        }

    }

    /**

     * Get the raw private key, x, without the parameters.

     *

     * @see getParameters

     */

    public BigInteger getX() {

        return x;

    }

    private void clearOldKey() {

        int i;

        if (this.encodedKey != null) {

            for (i = 0; i < this.encodedKey.length; i++) {

                this.encodedKey[i] = (byte)0x00;

            }

        }

        if (this.key != null) {

            for (i = 0; i < this.key.length; i++) {

                this.key[i] = (byte)0x00;

            }

        }

    }

    protected void parseKeyBits() throws InvalidKeyException {

        try {

            DerInputStream in = new DerInputStream(key);

            x = in.getBigInteger();

        } catch (IOException e) {

            InvalidKeyException ike = new InvalidKeyException(e.getMessage());

            ike.initCause(e);

            throw ike;

        }

    }

}