Encrypting with DES Using a Pass Phrase : DES Data Encryption Standard « Security « Java Tutorial

1. Java Tutorial
2. Security
3. DES Data Encryption Standard

import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.KeySpec;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

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

class DesEncrypter {
  Cipher ecipher;

  Cipher dcipher;

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

  DesEncrypter(String passPhrase) throws Exception {
    int iterationCount = 2;
    KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
    SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
    ecipher = Cipher.getInstance(key.getAlgorithm());
    dcipher = Cipher.getInstance(key.getAlgorithm());

    AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);

    ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
    dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
  }

  public String encrypt(String str) throws Exception {
    return new BASE64Encoder().encode(ecipher.doFinal(str.getBytes()));
  }

  public String decrypt(String str) throws Exception {
    return new String(dcipher.doFinal(new BASE64Decoder().decodeBuffer(str)));
  }
}

public class Main {
  public static void main(String[] argv) throws Exception {
    DesEncrypter encrypter = new DesEncrypter("My Pass Phrase!");

    String encrypted = encrypter.encrypt("Don't tell anybody!");

    String decrypted = encrypter.decrypt(encrypted);
  }
}