AES Password Encoder for Cayenne Models

AESPasswordEncoder.java

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

import org.apache.cayenne.conf.PasswordEncoding;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
 * @author mrg
 */
public class AESPasswordEncoder implements PasswordEncoding
{
  final static private int    cipherKeyLength = 16;
  final static private int    cipherKeyOffset = 0;
  final static private String cipherProvider  = "AES";

  /*
   * 
   */
  public String decodePassword(String encodedPassword, String key)
  {
    Cipher        decryptionCipher = null;
    SecretKeySpec keySpecification = null;

    key              = fixKey(key);
    keySpecification = new SecretKeySpec(key.getBytes(), cipherKeyOffset, cipherKeyLength, cipherProvider);

    try
    {
      decryptionCipher = Cipher.getInstance(cipherProvider);
      decryptionCipher.init(Cipher.DECRYPT_MODE, keySpecification);
      
      return new String(decryptionCipher.doFinal(new BASE64Decoder().decodeBuffer(encodedPassword)));
    }
    catch (Exception e)
    {
      // There was an exception getting the cipher -- report the error and
      // fall back to plain text (assumption is that encoding failed, too).
      e.printStackTrace();

      return encodedPassword;
    }
  }

  /*
   * 
   */
  public String encodePassword(String normalPassword, String key)
  {
    Cipher        encryptionCipher = null;
    SecretKeySpec keySpecification = null;

    key              = fixKey(key);
    keySpecification = new SecretKeySpec(key.getBytes(), cipherKeyOffset, cipherKeyLength, cipherProvider);

    try
    {
      encryptionCipher = Cipher.getInstance(cipherProvider);
      encryptionCipher.init(Cipher.ENCRYPT_MODE, keySpecification);

      return new BASE64Encoder().encode(encryptionCipher.doFinal(normalPassword.getBytes()));
    }
    catch (Exception e)
    {
      // There was an exception getting the cipher -- report the error and
      // fall back to plain text (assumption is that encoding failed, too).
      e.printStackTrace();

      return normalPassword;
    }
  }

  private String fixKey(String key)
  {
    if (key == null)
      key = "";
    else
      key = key.trim();

    while (key.length() < cipherKeyLength)
      key += getClass().getName();

    return key;
  }

  private void runTests()
  {
    String e, d, text = "myTestPassword!@#$%^";

    System.out.println("Test password: " + text);
    System.out.println();

    // Test with null for the AES key
    e = encodePassword(text, null);
    d = decodePassword(e, null);
    System.out.println("Encrypted: " + e);
    if (d.equals(text))
      System.out.println("Test with null key passed.");
    else
      System.out.println("**** TEST WITH NULL KEY FAILED.");

    // Test with "" for the AES key
    e = encodePassword(text, "");
    d = decodePassword(e, "");
    System.out.println("Encrypted: " + e);
    if (d.equals(text))
      System.out.println("Test with empty key passed.");
    else
      System.out.println("**** TEST WITH EMPTY KEY FAILED.");

    // Test with sub-16 character AES key
    e = encodePassword(text, "abcd1234efgh");
    d = decodePassword(e, "abcd1234efgh");
    System.out.println("Encrypted: " + e);
    if (d.equals(text))
      System.out.println("Test with sub-16 character key passed.");
    else
      System.out.println("**** TEST WITH SUB-16 CHARACTER KEY FAILED.");

    // Test with 16-character AES key
    e = encodePassword(text, "abcd1234efgh5678");
    d = decodePassword(e, "abcd1234efgh5678");
    System.out.println("Encrypted: " + e);
    if (d.equals(text))
      System.out.println("Test with 16-character key passed.");
    else
      System.out.println("**** TEST WITH 16-CHARACTER KEY FAILED.");

    // Test with 16-plus character AES key
    e = encodePassword(text, "abcd1234efgh5678ijkl");
    d = decodePassword(e, "abcd1234efgh5678ijkl");
    System.out.println("Encrypted: " + e);
    if (d.equals(text))
      System.out.println("Test with 16-plus character key passed.");
    else
      System.out.println("**** TEST WITH 16-PLUS CHARACTER KEY FAILED.");
  }

  private static void printUsage()
  {
    System.out.println("Usage:");
    System.out.println("  " + AESPasswordEncoder.class.getName() + " -d text-to-decrypt [key]");
    System.out.println("  " + AESPasswordEncoder.class.getName() + " -e text-to-encrypt [key]");
    System.out.println("  " + AESPasswordEncoder.class.getName() + " -t   (run tests)");
    System.out.println("");
    System.out.println("  The key should be 16 characters in length, but this is not required.");
  }

  public static void main(String[] args) 
  {
    if (args.length < 1)
    {
      printUsage();
      return;
    }

    AESPasswordEncoder encoder = new AESPasswordEncoder();
    String             flag = args[0];
    String             text = null;
    String             key  = null;

    if (args.length >= 2)
      text = args[1];
    if (args.length == 3)
      key = args[2];

    if (flag.equals("-d") && args.length >= 2)
      System.out.println(encoder.decodePassword(text, key));
    else if (flag.equals("-e") && args.length >= 2)
      System.out.println(encoder.encodePassword(text, key));
    else if (flag.equals("-t") && args.length == 1)
      encoder.runTests();
    else
      printUsage();
  }
}