/* CramMD5Util.java -- 
   Copyright (C) 2003, 2006 Free Software Foundation, Inc.

This file is a part of GNU Classpath.

GNU Classpath 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 2 of the License, or (at
your option) any later version.

GNU Classpath 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 GNU Classpath; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
USA

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package gnu.javax.crypto.sasl.crammd5;

import gnu.java.security.Registry;
import gnu.java.security.util.Util;
import gnu.javax.crypto.mac.HMacFactory;
import gnu.javax.crypto.mac.IMac;

import java.io.UnsupportedEncodingException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.InvalidKeyException;
import java.util.HashMap;

import javax.security.sasl.SaslException;

/**
 * A package-private CRAM-MD5-specific utility class.
 */
class CramMD5Util
{

  // Constants and variables
  // -------------------------------------------------------------------------

  // Constructor(s)
  // -------------------------------------------------------------------------

  private CramMD5Util()
  {
    super();
  }

  // Class methods
  // -------------------------------------------------------------------------

  static byte[] createMsgID() throws SaslException
  {
    // <process-ID.clock@hostname>
    final String encoded;
    try
      {
        encoded = Util.toBase64(Thread.currentThread().getName().getBytes(
                                                                          "UTF-8"));
      }
    catch (UnsupportedEncodingException x)
      {
        throw new SaslException("createMsgID()", x);
      }
    String hostname = "localhost";
    try
      {
        hostname = InetAddress.getLocalHost().getHostAddress();
      }
    catch (UnknownHostException ignored)
      {
      }

    final byte[] result;
    try
      {
        result = new StringBuffer().append("<").append(
                                                       encoded.substring(
                                                                         0,
                                                                         encoded.length())).append(
                                                                                                   ".").append(
                                                                                                               String.valueOf(System.currentTimeMillis())).append(
                                                                                                                                                                  "@").append(
                                                                                                                                                                              hostname).append(
                                                                                                                                                                                               ">").toString().getBytes(
                                                                                                                                                                                                                        "UTF-8");
      }
    catch (UnsupportedEncodingException x)
      {
        throw new SaslException("createMsgID()", x);
      }
    return result;
  }

  static byte[] createHMac(final char[] passwd, final byte[] data)
      throws InvalidKeyException, SaslException
  {
    final IMac mac = HMacFactory.getInstance(Registry.HMAC_NAME_PREFIX
                                             + Registry.MD5_HASH);
    final HashMap map = new HashMap();
    final byte[] km;
    try
      {
        km = new String(passwd).getBytes("UTF-8");
      }
    catch (UnsupportedEncodingException x)
      {
        throw new SaslException("createHMac()", x);
      }
    map.put(IMac.MAC_KEY_MATERIAL, km);
    mac.init(map);
    mac.update(data, 0, data.length);
    return mac.digest();
  }
}