Android Open Source - ivotingverification Crypto

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License

The source code is released under:

GNU General Public License

Java Source Code

/**
 * Copyright (C) 2013 Eesti Vabariigi Valimiskomisjon 
 * (Estonian National Electoral Committee), www.vvk.ee
 *//from w  w w  .  ja va 2  s . c  o  m
 * Written in 2013 by AS Finestmedia, www.finestmedia.ee
 * 
 * Vote-verification application for Estonian Internet voting system
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 **/
 
package ee.vvk.ivotingverification.util;

import java.io.IOException;
import java.io.StringReader;
import java.util.Enumeration;

import ext.org.bouncycastle.asn1.ASN1InputStream;
import ext.org.bouncycastle.asn1.ASN1Sequence;
import ext.org.bouncycastle.asn1.DERBitString;
import ext.org.bouncycastle.asn1.x509.RSAPublicKeyStructure;
import ext.org.bouncycastle.crypto.InvalidCipherTextException;
import ext.org.bouncycastle.crypto.encodings.OAEPEncoding;
import ext.org.bouncycastle.crypto.engines.RSAEngine;
import ext.org.bouncycastle.crypto.params.ParametersWithRandom;
import ext.org.bouncycastle.crypto.params.RSAKeyParameters;
import ext.org.bouncycastle.util.encoders.Hex;
import ext.org.bouncycastle.util.io.pem.PemObject;
import ext.org.bouncycastle.util.io.pem.PemReader;

/**
 * RSA-OAEP modification for the brute force verification.
 * 
 * @version 25.04.2013
 */
public class Crypto {

  private static String lastRandom;

  public static byte[] encrypt(String data, String random, String strkey)
      throws IOException, InvalidCipherTextException {
    return encrypt(data.getBytes(Util.ENCODING), new SecureRandomWrapper(
        random.getBytes(Util.ENCODING)), strkey);
  }

  public static byte[] encrypt(byte[] data, SecureRandomWrapper random,
      String strkey) throws IOException, InvalidCipherTextException {

    RSAKeyParameters key = readKey(strkey);

    OAEPEncoding engine = new OAEPEncoding(new RSAEngine());
    engine.init(true, new ParametersWithRandom(key, random));

    int bsz = engine.getInputBlockSize();
    byte[] res = Hex.encode(engine.processBlock(data, 0,
        Math.min(bsz, data.length)));

    lastRandom = new String(random.getLastBytes(), Util.ENCODING);
    return res;
  }

  private static RSAKeyParameters readKey(String pemstr) throws IOException {
    PemReader reader = null;
    PemObject pem;
    try {
      StringReader rr = new StringReader(pemstr);
      reader = new PemReader(rr);
      pem = reader.readPemObject();
    } finally {
      if (reader != null) {
        reader.close();
      }
    }

    ASN1InputStream stream = null;
    ASN1Sequence seq;
    try {
      stream = new ASN1InputStream(pem.getContent());
      seq = (ASN1Sequence) stream.readObject();

      Enumeration enm = seq.getObjects();
      enm.nextElement();

      stream = new ASN1InputStream(
          ((DERBitString) enm.nextElement()).getBytes());
      seq = (ASN1Sequence) stream.readObject();
    } finally {
      if (stream != null) {
        stream.close();
      }
    }
    RSAPublicKeyStructure pks = new RSAPublicKeyStructure(seq);
    return new RSAKeyParameters(false, pks.getModulus(),
        pks.getPublicExponent());
  }

  public static String getLastRandom() {
    return lastRandom;
  }
}

Java Source Code List

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