subjectpublickeyinfo.java

这是linux下ssl vpn的实现程序

/*
 *  SSL-Explorer
 *
 *  Copyright (C) 2003-2006 3SP LTD. All Rights Reserved
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2 of
 *  the License, or (at your option) any later version.
 *  This program 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 for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
			
package com.maverick.crypto.asn1.x509;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.Enumeration;

import com.maverick.crypto.asn1.ASN1EncodableVector;
import com.maverick.crypto.asn1.ASN1Sequence;
import com.maverick.crypto.asn1.ASN1TaggedObject;
import com.maverick.crypto.asn1.DERBitString;
import com.maverick.crypto.asn1.DEREncodable;
import com.maverick.crypto.asn1.DERInputStream;
import com.maverick.crypto.asn1.DERObject;
import com.maverick.crypto.asn1.DERSequence;

/**
 * The object that contains the public key stored in a certficate.
 * <p>
 * The getEncoded() method in the public keys in the JCE produces a DER
 * encoded one of these.
 */
public class SubjectPublicKeyInfo
    implements DEREncodable
{
    private AlgorithmIdentifier     algId;
    private DERBitString            keyData;

    public static SubjectPublicKeyInfo getInstance(
        ASN1TaggedObject obj,
        boolean          explicit)
    {
        return getInstance(ASN1Sequence.getInstance(obj, explicit));
    }

    public static SubjectPublicKeyInfo getInstance(
        Object  obj)
    {
        if (obj instanceof SubjectPublicKeyInfo)
        {
            return (SubjectPublicKeyInfo)obj;
        }
        else if (obj instanceof ASN1Sequence)
        {
            return new SubjectPublicKeyInfo((ASN1Sequence)obj);
        }

        throw new IllegalArgumentException("unknown object in factory");
    }

    public SubjectPublicKeyInfo(
        AlgorithmIdentifier algId,
        DEREncodable        publicKey)
    {
        this.keyData = new DERBitString(publicKey);
        this.algId = algId;
    }

    public SubjectPublicKeyInfo(
        AlgorithmIdentifier algId,
        byte[]              publicKey)
    {
        this.keyData = new DERBitString(publicKey);
        this.algId = algId;
    }

    public SubjectPublicKeyInfo(
        ASN1Sequence  seq)
    {
        Enumeration         e = seq.getObjects();

        this.algId = AlgorithmIdentifier.getInstance(e.nextElement());
        this.keyData = (DERBitString)e.nextElement();
    }

    public AlgorithmIdentifier getAlgorithmId()
    {
        return algId;
    }

    /**
     * for when the public key is an encoded object - if the bitstring
     * can't be decoded this routine throws an IOException.
     *
     * @exception IOException - if the bit string doesn't represent a DER
     * encoded object.
     */
    public DERObject getPublicKey()
        throws IOException
    {
        ByteArrayInputStream    bIn = new ByteArrayInputStream(keyData.getBytes());
        DERInputStream          dIn = new DERInputStream(bIn);

        return dIn.readObject();
    }

    /**
     * for when the public key is raw bits...
     */
    public DERBitString getPublicKeyData()
    {
        return keyData;
    }

    /**
     * Produce an object suitable for an ASN1OutputStream.
     * <pre>
     * SubjectPublicKeyInfo ::= SEQUENCE {
     *                          algorithm AlgorithmIdentifier,
     *                          publicKey BIT STRING }
     * </pre>
     */
    public DERObject getDERObject()
    {
        ASN1EncodableVector  v = new ASN1EncodableVector();

        v.add(algId);
        v.add(keyData);

        return new DERSequence(v);
    }
}