de.mpg.escidoc.services.aa.crypto.RSAEncoder.java Source code

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Here is the source code for de.mpg.escidoc.services.aa.crypto.RSAEncoder.java

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/*
*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at license/ESCIDOC.LICENSE
* or http://www.escidoc.org/license.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at license/ESCIDOC.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/

/*
* Copyright 2006-2012 Fachinformationszentrum Karlsruhe Gesellschaft
* fr wissenschaftlich-technische Information mbH and Max-Planck-
* Gesellschaft zur Frderung der Wissenschaft e.V.
* All rights reserved. Use is subject to license terms.
*/

package de.mpg.escidoc.services.aa.crypto;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.StringWriter;
import java.math.BigInteger;
import java.net.URLEncoder;
import java.security.Key;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.KeySpec;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;

import de.mpg.escidoc.services.aa.Config;
import de.mpg.escidoc.services.aa.util.ResourceUtil;

/**
 * TODO Description
 *
 * @author franke (initial creation)
 * @author $Author$ (last modification)
 * @version $Revision$ $LastChangedDate$
 *
 */
public class RSAEncoder {

    private RSAEncoder() {
    }

    public static String rsaEncrypt(String string) throws Exception {
        StringWriter resultWriter = new StringWriter();
        byte[] bytes = string.getBytes("UTF-8");
        PublicKey pubKey = (PublicKey) readKeyFromFile(Config.getProperty("escidoc.aa.public.key.file"), true);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        int blockSize = 245;
        for (int i = 0; i < bytes.length; i += blockSize) {
            byte[] result = cipher.doFinal(bytes, i, (i + blockSize < bytes.length ? blockSize : bytes.length - i));
            if (i > 0) {
                resultWriter.write("&");
            }
            resultWriter.write("auth=");
            resultWriter.write(URLEncoder.encode(new String(Base64.encodeBase64(result)), "ISO-8859-1"));
        }
        return resultWriter.toString();

    }

    public static String rsaDecrypt(String[] string) throws Exception {

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PrivateKey privateKey = (PrivateKey) readKeyFromFile(Config.getProperty("escidoc.aa.private.key.file"),
                false);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        for (String part : string) {
            byte[] inArr = Base64.decodeBase64(part.getBytes("UTF-8"));
            baos.write(cipher.doFinal(inArr));
            baos.flush();
        }

        return new String(baos.toByteArray(), "UTF-8");

    }

    public static Key readKeyFromFile(String keyFileName, boolean publ) throws Exception {
        InputStream in = ResourceUtil.getResourceAsStream(keyFileName, RSAEncoder.class.getClassLoader());
        ObjectInputStream oin = new ObjectInputStream(new BufferedInputStream(in));
        try {
            BigInteger m = (BigInteger) oin.readObject();
            BigInteger e = (BigInteger) oin.readObject();
            KeySpec keySpec;
            if (publ) {
                keySpec = new RSAPublicKeySpec(m, e);
            } else {
                keySpec = new RSAPrivateKeySpec(m, e);
            }
            KeyFactory fact = KeyFactory.getInstance("RSA");
            if (publ) {
                PublicKey pubKey = fact.generatePublic(keySpec);
                return pubKey;
            } else {
                PrivateKey privKey = fact.generatePrivate(keySpec);
                return privKey;
            }
        } catch (Exception e) {
            throw new RuntimeException("Error reading key from file", e);
        } finally {
            oin.close();
        }
    }

}