authoritykeyidentifier.java

来自「《移动Agent技术》一书的所有章节源代码。」· Java 代码 · 共 172 行

package org.bouncycastle.asn1.x509;

import java.math.BigInteger;

import java.util.Enumeration;

import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.digests.SHA1Digest;
import org.bouncycastle.asn1.*;

/**
 * <pre>
 * id-ce-authorityKeyIdentifier OBJECT IDENTIFIER ::=  { id-ce 35 }
 *
 *   AuthorityKeyIdentifier ::= SEQUENCE {
 *      keyIdentifier             [0] IMPLICIT KeyIdentifier           OPTIONAL,
 *      authorityCertIssuer       [1] IMPLICIT GeneralNames            OPTIONAL,
 *      authorityCertSerialNumber [2] IMPLICIT CertificateSerialNumber OPTIONAL  }
 *
 *   KeyIdentifier ::= OCTET STRING
 * </pre>
 *
 */
public class AuthorityKeyIdentifier
    implements DEREncodable
{
    DEROctetString keyidentifier=null;
    GeneralNames certissuer=null;
    DERInteger certserno=null;

    public AuthorityKeyIdentifier(
        DERConstructedSequence   seq)
    {
        Enumeration e = seq.getObjects();

        while (e.hasMoreElements())
        {
            DERTaggedObject o = (DERTaggedObject)e.nextElement();

            switch (o.getTagNo())
            {
            case 0:
                this.keyidentifier= (DEROctetString)o.getObject();
                break;

            case 1:
                if (o.getObject() instanceof DERConstructedSequence)
                {
                    this.certissuer = new GeneralNames((DERConstructedSequence)o.getObject());
                }
                else   
                {
                    // as it's implicitly tagged we can loose the"sequence"
                    // if there is only one object.
                    //
                    DERConstructedSequence s = new DERConstructedSequence();

                    s.addObject(o.getObject());

                    this.certissuer = new GeneralNames(s);
                }
                break;
            case 2:
                //
                // implicit tagging again...
                //
                DEROctetString          oct = (DEROctetString)o.getObject();

                this.certserno = new DERInteger(new BigInteger(oct.getOctets()));
                break;
            default:
                throw new IllegalArgumentException("illegal tag");
            }
        }
    }

    /**
     *
     * Calulates the keyidentifier using a SHA1 hash over the BIT STRING
     * from SubjectPublicKeyInfo as defined in RFC2459.
     *
     * Example of making a AuthorityKeyIdentifier:
     * <pre>
     *   SubjectPublicKeyInfo apki = new SubjectPublicKeyInfo((DERConstructedSequence)new DERInputStream(
     *       new ByteArrayInputStream(publicKey.getEncoded())).readObject());
     *   AuthorityKeyIdentifier aki = new AuthorityKeyIdentifier(apki);
     * </pre>
     *
     **/
    public AuthorityKeyIdentifier(
        SubjectPublicKeyInfo    spki)
    {
        Digest  digest = new SHA1Digest();
        byte[]  resBuf = new byte[digest.getDigestSize()];

        byte[] bytes = spki.getPublicKeyData().getBytes();
        digest.update(bytes, 0, bytes.length);
        digest.doFinal(resBuf, 0);
        this.keyidentifier=new DEROctetString(resBuf);
    }

    /**
     * create an AuthorityKeyIdentifier with the GeneralNames tag and
     * the serial number provided as well.
     */
    public AuthorityKeyIdentifier(
        SubjectPublicKeyInfo    spki,
        GeneralNames            name,
        BigInteger              serialNumber)
    {
        Digest  digest = new SHA1Digest();
        byte[]  resBuf = new byte[digest.getDigestSize()];

        byte[] bytes = spki.getPublicKeyData().getBytes();
        digest.update(bytes, 0, bytes.length);
        digest.doFinal(resBuf, 0);

        this.keyidentifier = new DEROctetString(resBuf);
        this.certissuer = name;
        this.certserno = new DERInteger(serialNumber);
    }

    public byte[] getKeyIdentifier()
    {
        if (keyidentifier != null)
        {
            return keyidentifier.getOctets();
        }

        return null;
    }

     /**
     * <pre>
     *   AuthorityKeyIdentifier ::= SEQUENCE {
     *      keyIdentifier             [0] IMPLICIT KeyIdentifier           OPTIONAL,
     *      authorityCertIssuer       [1] IMPLICIT GeneralNames            OPTIONAL,
     *      authorityCertSerialNumber [2] IMPLICIT CertificateSerialNumber OPTIONAL  }
     *
     *   KeyIdentifier ::= OCTET STRING
     * </pre>
     */
    public DERObject getDERObject()
    {
        DERConstructedSequence  seq = new DERConstructedSequence();

        if (keyidentifier != null)
        {
            seq.addObject(new DERTaggedObject(false, 0, keyidentifier));
        }

        if (certissuer != null)
        {
			certissuer.markImplicit(true);
            seq.addObject(new DERTaggedObject(false, 1, certissuer));
        }

        if (certserno != null)
        {
            seq.addObject(new DERTaggedObject(false, 2, certserno));
        }


        return seq;
    }

    public String toString()
    {
        return ("AuthorityKeyIdentifier: KeyID(" + this.keyidentifier.getOctets() + ")");
    }
}