Package org.teiid.core.crypto

Source Code of org.teiid.core.crypto.DhKeyGenerator

/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.  Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/

package org.teiid.core.crypto;

import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.AlgorithmParameterGenerator;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.util.Properties;

import javax.crypto.KeyAgreement;
import javax.crypto.spec.DHParameterSpec;

import org.teiid.core.TeiidRuntimeException;


/**
* Helper class that supports anonymous ephemeral Diffie-Hellman
*
* Parameters are stored in the dh.properties file
*/
public class DhKeyGenerator {

  private static String ALGORITHM = "DiffieHellman"; //$NON-NLS-1$
  private static String DIGEST = "SHA-256"; //$NON-NLS-1$
  private static DHParameterSpec DH_SPEC;

  static {
    Properties props = new Properties();
    InputStream is = null;
    try {
      is = DhKeyGenerator.class.getResourceAsStream("dh.properties"); //$NON-NLS-1$
      props.load(is);
    } catch (IOException e) {
      throw new TeiidRuntimeException(e);
    } finally {
      try {
        if (is != null) {
          is.close();
        }
      } catch (IOException e) {
      }
    }
    BigInteger p = new BigInteger(props.getProperty("p")); //$NON-NLS-1$
    BigInteger g = new BigInteger(props.getProperty("g")); //$NON-NLS-1$
    DH_SPEC = new DHParameterSpec(p, g, Integer.parseInt(props
        .getProperty("l"))); //$NON-NLS-1$
  }

  private PrivateKey privateKey;

  /*
   * TODO: add support for configurable key sizes
   */
  private int keySize = SymmetricCryptor.DEFAULT_KEY_BITS;

  public byte[] createPublicKey() throws CryptoException {
    try {
      KeyPairGenerator keyGen = KeyPairGenerator.getInstance(ALGORITHM);
      keyGen.initialize(DH_SPEC);
      KeyPair keypair = keyGen.generateKeyPair();

      privateKey = keypair.getPrivate();
      PublicKey publicKey = keypair.getPublic();

      return publicKey.getEncoded();
    } catch (NoSuchAlgorithmException e) {
      throw new CryptoException(e);
    } catch (InvalidAlgorithmParameterException e) {
      throw new CryptoException(e);
    }
  }

  public SymmetricCryptor getSymmetricCryptor(byte[] peerPublicKeyBytes)
      throws CryptoException {
    if (privateKey == null) {
      throw new IllegalStateException(
          "KeyGenerator did not successfully generate public key"); //$NON-NLS-1$
    }
    try {
      X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(
          peerPublicKeyBytes);
      KeyFactory keyFact = KeyFactory.getInstance(ALGORITHM);
      PublicKey publicKey = keyFact.generatePublic(x509KeySpec);

      KeyAgreement ka = KeyAgreement.getInstance(ALGORITHM);
      ka.init(privateKey);
      ka.doPhase(publicKey, true);
      byte[] secret = ka.generateSecret();

      MessageDigest sha = MessageDigest.getInstance(DIGEST);
      byte[] hash = sha.digest(secret);
      byte[] symKey = new byte[keySize / 8];
      System.arraycopy(hash, 0, symKey, 0, symKey.length);
      return SymmetricCryptor.getSymmectricCryptor(symKey);
    } catch (NoSuchAlgorithmException e) {
      throw new CryptoException(e);
    } catch (InvalidKeySpecException e) {
      throw new CryptoException(e);
    } catch (InvalidKeyException e) {
      throw new CryptoException(e);
    }
  }

  /**
   * Can be used to generate new parameters
   */
  public static void main(String[] args) throws Exception {
    AlgorithmParameterGenerator paramGen = AlgorithmParameterGenerator
        .getInstance(ALGORITHM);
    paramGen.init(1024);

    AlgorithmParameters params = paramGen.generateParameters();

    DHParameterSpec dhSpec = params.getParameterSpec(DHParameterSpec.class);
    System.out.println("l=" + dhSpec.getL());
    System.out.println("g=" + dhSpec.getG());
    System.out.println("p=" +dhSpec.getP());
  }

}
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