de.tsenger.animamea.asn1.AmRSAPublicKey.java Source code

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Here is the source code for de.tsenger.animamea.asn1.AmRSAPublicKey.java

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/**
 *  Copyright 2011, Tobias Senger
 *  
 *  This file is part of animamea.
 *
 *  Animamea 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  Animamea 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 animamea.  If not, see <http://www.gnu.org/licenses/>.
 */
package de.tsenger.animamea.asn1;

import java.io.IOException;
import java.math.BigInteger;
import java.security.interfaces.RSAPublicKey;

import org.bouncycastle.asn1.ASN1Encoding;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.BERTags;
import org.bouncycastle.asn1.DERTaggedObject;

/**
 * @author Tobias Senger (tobias@t-senger.de)
 *
 */
public class AmRSAPublicKey extends AmPublicKey implements RSAPublicKey {

    private static final long serialVersionUID = -7184069684377504157L;

    private final String algorithm = "RSA";
    private final String format = "CVC";

    private DERTaggedObject n = null;
    private DERTaggedObject e = null;

    /**
     * @param seq
     */
    public AmRSAPublicKey(ASN1Sequence seq) {
        super(seq);
        decode(seq);
    }

    public AmRSAPublicKey(String oidString, BigInteger n, BigInteger e) {
        super(oidString);
        this.n = new DERTaggedObject(false, 1, new ASN1Integer(n));
        this.e = new DERTaggedObject(false, 2, new ASN1Integer(e));
        vec.add(this.n);
        vec.add(this.e);
    }

    /* (non-Javadoc)
     * @see java.security.Key#getAlgorithm()
     */
    @Override
    public String getAlgorithm() {
        return algorithm;
    }

    /* (non-Javadoc)
     * @see java.security.Key#getEncoded()
     */
    @Override
    public byte[] getEncoded() {
        vec.add(this.n);
        vec.add(this.e);
        try {
            return super.getEncoded(ASN1Encoding.DER);
        } catch (IOException e1) {
            return null;
        }
    }

    /* (non-Javadoc)
     * @see java.security.Key#getFormat()
     */
    @Override
    public String getFormat() {
        return format;
    }

    /* (non-Javadoc)
     * @see de.tsenger.animamea.asn1.AmPublicKey#decode(org.bouncycastle.asn1.ASN1Sequence)
     */
    @Override
    protected void decode(ASN1Sequence seq) {
        for (int i = 1; i < seq.size(); i++) {
            DERTaggedObject to = (DERTaggedObject) seq.getObjectAt(i);
            switch (to.getTagNo()) {
            case 1:
                n = to;
                break;
            case 2:
                e = to;
                break;
            }
        }

    }

    /* (non-Javadoc)
     * @see java.security.interfaces.RSAKey#getModulus()
     */
    @Override
    public BigInteger getModulus() {
        if (n == null)
            return null;
        ASN1Integer derInt = (ASN1Integer) n.getObjectParser(BERTags.INTEGER, false);
        return derInt.getPositiveValue();
    }

    /* (non-Javadoc)
     * @see java.security.interfaces.RSAPublicKey#getPublicExponent()
     */
    @Override
    public BigInteger getPublicExponent() {
        if (e == null)
            return null;
        ASN1Integer derInt = (ASN1Integer) e.getObjectParser(BERTags.INTEGER, false);
        return derInt.getPositiveValue();
    }

}