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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * 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.

 *

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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.X509Key;

/**

 * Key implementation for RSA public keys.

 *

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

 *

 * @see RSAPrivateCrtKeyImpl

 * @see RSAKeyFactory

 *

 * @since   1.5

 * @author  Andreas Sterbenz

 */

public final class RSAPublicKeyImpl extends X509Key implements RSAPublicKey {

    private static final long serialVersionUID = 2644735423591199609L;

    private BigInteger n;       // modulus

    private BigInteger e;       // public exponent

    /**

     * Construct a key from its components. Used by the

     * RSAKeyFactory and the RSAKeyPairGenerator.

     */

    public RSAPublicKeyImpl(BigInteger n, BigInteger e)

            throws InvalidKeyException {

        this.n = n;

        this.e = e;

        RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e);

        // generate the encoding

        algid = RSAPrivateCrtKeyImpl.rsaId;

        try {

            DerOutputStream out = new DerOutputStream();

            out.putInteger(n);

            out.putInteger(e);

            byte[] keyArray =

                new DerValue(DerValue.tag_Sequence,

                             out.toByteArray()).toByteArray();

            setKey(new BitArray(keyArray.length*8, keyArray));

        } catch (IOException exc) {

            // should never occur

            throw new InvalidKeyException(exc);

        }

    }

    /**

     * Construct a key from its encoding. Used by RSAKeyFactory.

     */

    public RSAPublicKeyImpl(byte[] encoded) throws InvalidKeyException {

        decode(encoded);

        RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e);

    }

    // see JCA doc

    public String getAlgorithm() {

        return "RSA";

    }

    // see JCA doc

    public BigInteger getModulus() {

        return n;

    }

    // see JCA doc

    public BigInteger getPublicExponent() {

        return e;

    }

    /**

     * Parse the key. Called by X509Key.

     */

    protected void parseKeyBits() throws InvalidKeyException {

        try {

            DerInputStream in = new DerInputStream(getKey().toByteArray());

            DerValue derValue = in.getDerValue();

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

                throw new IOException("Not a SEQUENCE");

            }

            DerInputStream data = derValue.data;

            n = data.getPositiveBigInteger();

            e = data.getPositiveBigInteger();

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

                throw new IOException("Extra data available");

            }

        } catch (IOException e) {

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

        }

    }

    // return a string representation of this key for debugging

    public String toString() {

        return "Sun RSA public key, " + n.bitLength() + " bits\n  modulus: "

                + n + "\n  public exponent: " + e;

    }

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

        return new KeyRep(KeyRep.Type.PUBLIC,

                        getAlgorithm(),

                        getFormat(),

                        getEncoded());

    }

}