content: /*
   * Copyright (C) 2013 Glyptodon LLC
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  package net.sourceforge.guacamole.net.auth.mysql.service;
  
  import java.io.UnsupportedEncodingException;
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  import java.util.Arrays;
  import javax.xml.bind.DatatypeConverter;
  
  /**
   * Provides a SHA-256 based implementation of the password encryption functionality.
   * @author James Muehlner
   */
  public class SHA256PasswordEncryptionService implements PasswordEncryptionService {
  
      @Override
      public boolean checkPassword(String password, byte[] hashedPassword,
          byte[] salt) {
  
          // Compare bytes of password in credentials against hashed password
          byte[] passwordBytes = createPasswordHash(password, salt);
          return Arrays.equals(passwordBytes, hashedPassword);
  
      }
  
      @Override
      public byte[] createPasswordHash(String password, byte[] salt) {
  
          try {
  
              // Build salted password
              StringBuilder builder = new StringBuilder();
              builder.append(password);
              builder.append(DatatypeConverter.printHexBinary(salt));
  
              // Hash UTF-8 bytes of salted password
              MessageDigest md = MessageDigest.getInstance("SHA-256");
              md.update(builder.toString().getBytes("UTF-8"));
              return md.digest();
  
          }
  
          // Should not happen
          catch (UnsupportedEncodingException ex) {
              throw new RuntimeException(ex);
          }
  
          // Should not happen
          catch (NoSuchAlgorithmException ex) {
              throw new RuntimeException(ex);
          }
  
      }
  }
  