/*

 * Copyright 2003-2005 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 sun.security.rsa;

import java.io.IOException;

import java.math.BigInteger;

import java.security.*;

import java.security.interfaces.*;

import sun.security.util.*;

import sun.security.x509.AlgorithmId;

import sun.security.pkcs.PKCS8Key;

/**

 * Key implementation for RSA private keys, CRT form. For non-CRT private

 * keys, see RSAPrivateKeyImpl. We need separate classes to ensure

 * correct behavior in instanceof checks, etc.

 *

 * Note: RSA keys must be at least 512 bits long

 *

 * @see RSAPrivateKeyImpl

 * @see RSAKeyFactory

 *

 * @since   1.5

 * @author  Andreas Sterbenz

 */

public final class RSAPrivateCrtKeyImpl

        extends PKCS8Key implements RSAPrivateCrtKey {

    private static final long serialVersionUID = -1326088454257084918L;

    private BigInteger n;       // modulus

    private BigInteger e;       // public exponent

    private BigInteger d;       // private exponent

    private BigInteger p;       // prime p

    private BigInteger q;       // prime q

    private BigInteger pe;      // prime exponent p

    private BigInteger qe;      // prime exponent q

    private BigInteger coeff;   // CRT coeffcient

    // algorithmId used to identify RSA keys

    final static AlgorithmId rsaId =

        new AlgorithmId(AlgorithmId.RSAEncryption_oid);

    /**

     * Generate a new key from its encoding. Returns a CRT key if possible

     * and a non-CRT key otherwise. Used by RSAKeyFactory.

     */

    public static RSAPrivateKey newKey(byte[] encoded)

            throws InvalidKeyException {

        RSAPrivateCrtKeyImpl key = new RSAPrivateCrtKeyImpl(encoded);

        if (key.getPublicExponent().signum() == 0) {

            // public exponent is missing, return a non-CRT key

            return new RSAPrivateKeyImpl(

                key.getModulus(),

                key.getPrivateExponent()

            );

        } else {

            return key;

        }

    }

    /**

     * Construct a key from its encoding. Called from newKey above.

     */

    RSAPrivateCrtKeyImpl(byte[] encoded) throws InvalidKeyException {

        decode(encoded);

        RSAKeyFactory.checkKeyLength(n);

    }

    /**

     * Construct a key from its components. Used by the

     * RSAKeyFactory and the RSAKeyPairGenerator.

     */

    RSAPrivateCrtKeyImpl(BigInteger n, BigInteger e, BigInteger d,

            BigInteger p, BigInteger q, BigInteger pe, BigInteger qe,

            BigInteger coeff) throws InvalidKeyException {

        this.n = n;

        this.e = e;

        this.d = d;

        this.p = p;

        this.q = q;

        this.pe = pe;

        this.qe = qe;

        this.coeff = coeff;

        RSAKeyFactory.checkKeyLength(n);

        // generate the encoding

        algid = rsaId;

        try {

            DerOutputStream out = new DerOutputStream();

            out.putInteger(0); // version must be 0

            out.putInteger(n);

            out.putInteger(e);

            out.putInteger(d);

            out.putInteger(p);

            out.putInteger(q);

            out.putInteger(pe);

            out.putInteger(qe);

            out.putInteger(coeff);

            DerValue val =

                new DerValue(DerValue.tag_Sequence, out.toByteArray());

            key = val.toByteArray();

        } catch (IOException exc) {

            // should never occur

            throw new InvalidKeyException(exc);

        }

    }

    // see JCA doc

    public String getAlgorithm() {

        return "RSA";

    }

    // see JCA doc

    public BigInteger getModulus() {

        return n;

    }

    // see JCA doc

    public BigInteger getPublicExponent() {

        return e;

    }

    // see JCA doc

    public BigInteger getPrivateExponent() {

        return d;

    }

    // see JCA doc

    public BigInteger getPrimeP() {

        return p;

    }

    // see JCA doc

    public BigInteger getPrimeQ() {

        return q;

    }

    // see JCA doc

    public BigInteger getPrimeExponentP() {

        return pe;

    }

    // see JCA doc

    public BigInteger getPrimeExponentQ() {

        return qe;

    }

    // see JCA doc

    public BigInteger getCrtCoefficient() {

        return coeff;

    }

    /**

     * Parse the key. Called by PKCS8Key.

     */

    protected void parseKeyBits() throws InvalidKeyException {

        try {

            DerInputStream in = new DerInputStream(key);

            DerValue derValue = in.getDerValue();

            if (derValue.tag != DerValue.tag_Sequence) {

                throw new IOException("Not a SEQUENCE");

            }

            DerInputStream data = derValue.data;

            int version = data.getInteger();

            if (version != 0) {

                throw new IOException("Version must be 0");

            }

            n = getBigInteger(data);

            e = getBigInteger(data);

            d = getBigInteger(data);

            p = getBigInteger(data);

            q = getBigInteger(data);

            pe = getBigInteger(data);

            qe = getBigInteger(data);

            coeff = getBigInteger(data);

            if (derValue.data.available() != 0) {

                throw new IOException("Extra data available");

            }

        } catch (IOException e) {

            throw new InvalidKeyException("Invalid RSA private key", e);

        }

    }

    /**

     * Read a BigInteger from the DerInputStream.

     */

    static BigInteger getBigInteger(DerInputStream data) throws IOException {

        BigInteger b = data.getBigInteger();

        /*

         * Some implementations do not correctly encode ASN.1 INTEGER values

         * in 2's complement format, resulting in a negative integer when

         * decoded. Correct the error by converting it to a positive integer.

         *

         * See CR 6255949

         */

        if (b.signum() < 0) {

            b = new BigInteger(1, b.toByteArray());

        }

        return b;

    }

    // return a string representation of this key for debugging

    public String toString() {

        StringBuffer sb = new StringBuffer();

        sb.append("Sun RSA private CRT key, ");

        sb.append(n.bitLength());

        sb.append(" bits\n  modulus:          ");

        sb.append(n);

        sb.append("\n  public exponent:  ");

        sb.append(e);

        sb.append("\n  private exponent: ");

        sb.append(d);

        sb.append("\n  prime p:          ");

        sb.append(p);

        sb.append("\n  prime q:          ");

        sb.append(q);

        sb.append("\n  prime exponent p: ");

        sb.append(pe);

        sb.append("\n  prime exponent q: ");

        sb.append(qe);

        sb.append("\n  crt coefficient:  ");

        sb.append(coeff);

        return sb.toString();

    }

}