Tagliamo la testa al toro.
Qualche anno fa un utente aveva postato questa classe: funziona bene.

codice:
import javax.crypto.*;
import javax.crypto.spec.*;
import java.io.*;

public class DesEncrypter {
   Cipher ecipher;
   Cipher dcipher;

   // 8-byte Salt
   byte[] salt = {(byte)0xA9, (byte)0x9B, (byte)0xC8, (byte)0x32,
                  (byte)0x56, (byte)0x35, (byte)0xE3, (byte)0x03
                 };

   // Iteration count
   int iterationCount = 19;

   public DesEncrypter(String passPhrase) {
      try {
         // Create the key
         PBEKeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
         SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
         ecipher = Cipher.getInstance(key.getAlgorithm());
         dcipher = Cipher.getInstance(key.getAlgorithm());

         // Prepare the parameter to the ciphers
         PBEParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);

         // Create the ciphers
         ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
         dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
      } catch (Exception e) { e.printStackTrace(); }
   }

   public String encrypt(String str) {
      String ret = null;
      try {
         // Encode the string into bytes using utf-8
         byte[] utf8 = str.getBytes("UTF8");

         // Encrypt
         byte[] enc = ecipher.doFinal(utf8);

         // Encode bytes to base64 to get a string
         ret = new sun.misc.BASE64Encoder().encode(enc);
      } catch (Exception e) { e.printStackTrace(); } 
      return ret;
  }

  public String decrypt(String str) {
     String ret = null;
     try {
        // Decode base64 to get bytes
        byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

        // Decrypt
        byte[] utf8 = dcipher.doFinal(dec);

        // Decode using utf-8
        ret = new String(utf8, "UTF8");
     } catch (Exception e) { e.printStackTrace(); }
     return ret;
   }
}
Esempio d'uso:

codice:
public class Prova {
   public static void main(String[] args) throws Exception {
      String tuaPassword = "pincopallino";
      DesEncrypter enc = new DesEncrypter("tua chiave");
      String criptata = enc.encrypt(tuaPassword);
      System.out.println("Password criptata: " + criptata);
      System.out.println("Password decriptata: " + enc.decrypt(criptata));
   }
}
Ciao.