subjectpublickeyinfo.java

来自「《移动Agent技术》一书的所有章节源代码。」· Java 代码 · 共 94 行

package org.bouncycastle.asn1.x509;

import java.io.*;
import java.util.Enumeration;
import java.math.BigInteger;

import org.bouncycastle.asn1.*;
import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;

/**
 * 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 SubjectPublicKeyInfo(
        AlgorithmIdentifier algId,
        DERObject           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(
        DERConstructedSequence  seq)
    {
        Enumeration         e = seq.getObjects();

        this.algId = new AlgorithmIdentifier((DERConstructedSequence)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 (DERObject)dIn.readObject();
    }

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

    /**
     * <pre>
     * SubjectPublicKeyInfo ::= SEQUENCE {
     *                          algorithm AlgorithmIdentifier,
     *                          publicKey BIT STRING }
     * </pre>
     */
    public DERObject getDERObject()
    {
        DERConstructedSequence  seq = new DERConstructedSequence();

        seq.addObject(algId);
		seq.addObject(keyData);

        return seq;
    }
}