Data Encryption Standard (DES) Algorithm

1. DES Key

Create a DES Key.

    KeyGenerator keygenerator = KeyGenerator.getInstance("DES");
    SecretKey myDesKey = keygenerator.generateKey();

2. Cipher Info

Create a Cipher instance from Cipher class, specify the following information and separated by a slash (/).

• Algorithm name
• Mode (optional)
• Padding scheme (optional)

    Cipher desCipher;
    // Create the cipher 
    desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

Note
DES = Data Encryption Standard.
ECB = Electronic Codebook mode.
PKCS5Padding = PKCS #5-style padding.

In this case, you created a DES (Data Encryption Standard) cipher in Electronic Codebook mode, with PKCS #5-style padding.

3. Convert It

Convert String into Byte[] array format.

    byte[] text = "No body can see me".getBytes();

4. Encrypt It

Make Cipher in encrypt mode, and encrypt it with Cipher.doFinal() method.

    desCipher.init(Cipher.ENCRYPT_MODE, myDesKey);
    byte[] textEncrypted = desCipher.doFinal(text);

5. Decrypt It

Make Cipher in decrypt mode, and decrypt it with Cipher.doFinal() method as well.

    desCipher.init(Cipher.DECRYPT_MODE, myDesKey);
    byte[] textDecrypted = desCipher.doFinal(textEncrypted);

6. Full Example

Full Example to show how to use Java’s JCE to encrypt and decrypt text in DES mechanism.

package com.mkyong.util;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;

public class JEncrytion
{    
 public static void main(String[] argv) {
  
  try{

      KeyGenerator keygenerator = KeyGenerator.getInstance("DES");
      SecretKey myDesKey = keygenerator.generateKey();
      
      Cipher desCipher;

      // Create the cipher 
      desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
      
      // Initialize the cipher for encryption
      desCipher.init(Cipher.ENCRYPT_MODE, myDesKey);

      //sensitive information
      byte[] text = "No body can see me".getBytes();

      System.out.println("Text [Byte Format] : " + text);
      System.out.println("Text : " + new String(text));
     
      // Encrypt the text
      byte[] textEncrypted = desCipher.doFinal(text);

      System.out.println("Text Encryted : " + textEncrypted);
      
      // Initialize the same cipher for decryption
      desCipher.init(Cipher.DECRYPT_MODE, myDesKey);

      // Decrypt the text
      byte[] textDecrypted = desCipher.doFinal(textEncrypted);
      
      System.out.println("Text Decryted : " + new String(textDecrypted));
      
  }catch(NoSuchAlgorithmException e){
   e.printStackTrace();
  }catch(NoSuchPaddingException e){
   e.printStackTrace();
  }catch(InvalidKeyException e){
   e.printStackTrace();
  }catch(IllegalBlockSizeException e){
   e.printStackTrace();
  }catch(BadPaddingException e){
   e.printStackTrace();
  } 
    
 }
}

Output

Text [Byte Format] : [B@19b5393
Text : No body can see me
Text Encryted : [B@4e79f1
Text Decryted : No body can see me