edu.amrita.selabs.cumulus.lib.RSAKeyUtil.java Source code

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Here is the source code for edu.amrita.selabs.cumulus.lib.RSAKeyUtil.java

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/*
 * This file is part of Cumulus software system developed at SE Labs, Amrita University.
 *
 * Cumulus is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3.0 of the License, or (at your option) any later version.
 *
 * Cumulus 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

package edu.amrita.selabs.cumulus.lib;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import org.bouncycastle.util.encoders.Base64;

public class RSAKeyUtil {

    private KeyFactory fact = null;
    private PublicKey pubKey = null;
    private PrivateKey privKey = null;

    public void genKeyPair() throws NoSuchAlgorithmException {
        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        kpg.initialize(2048);
        KeyPair kp = kpg.genKeyPair();
        pubKey = kp.getPublic();
        privKey = kp.getPrivate();
    }

    public String getEncodedPrivateKey() throws NoSuchAlgorithmException, InvalidKeySpecException {
        initKeyFactory();

        PKCS8EncodedKeySpec priv = fact.getKeySpec(privKey, PKCS8EncodedKeySpec.class);

        String s = new String(Base64.encode(priv.getEncoded()));

        return s;
    }

    public String getEncodedPublicKey() throws NoSuchAlgorithmException, InvalidKeySpecException {
        initKeyFactory();
        X509EncodedKeySpec pub = fact.getKeySpec(pubKey, X509EncodedKeySpec.class);

        String s = new String(Base64.encode(pub.getEncoded()));
        return s;
    }

    public PublicKey decodePublicKey(String s) throws NoSuchAlgorithmException, InvalidKeySpecException {
        initKeyFactory();
        X509EncodedKeySpec pubSpec = new X509EncodedKeySpec(Base64.decode(s));

        pubKey = fact.generatePublic(pubSpec);
        return pubKey;
    }

    public PrivateKey decodePrivateKey(String s) throws NoSuchAlgorithmException, InvalidKeySpecException {
        initKeyFactory();
        PKCS8EncodedKeySpec privSpec = new PKCS8EncodedKeySpec(Base64.decode(s));

        privKey = fact.generatePrivate(privSpec);

        return privKey;
    }

    public PrivateKey getPrivateKey() {
        return privKey;
    }

    public PublicKey getPublicKey() {
        return pubKey;
    }

    private void initKeyFactory() throws NoSuchAlgorithmException {
        if (fact == null)
            fact = KeyFactory.getInstance("RSA");
    }

}