Password Based Encryption

pbe.groovy

import java.security.*
import javax.crypto.*
import javax.crypto.spec.*
import javax.xml.bind.DatatypeConverter

class PBE {
	def secretKey;
	def salt = getSalt();
	def iterations = 65536  ;
	def keySize = 256;
	def ivBytes;
	def saltBytes = getSalt()

	def getSalt() {
	    def salt = new byte[20]
	    SecureRandom.getInstance("SHA1PRNG").nextBytes(salt)
	    return new String(salt);
	}

	def encrypt(char[] plaintext)  {
	    byte[] saltBytes = salt.getBytes();

	    // def skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1"); 
	    def skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA512"); // only in java 8, uncomment above for java 7
	    def spec = new PBEKeySpec(plaintext, saltBytes, iterations, keySize);
	    secretKey = skf.generateSecret(spec);
	    def secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");

	    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
	    cipher.init(Cipher.ENCRYPT_MODE, secretSpec);
	    def params = cipher.getParameters();
	    ivBytes = params.getParameterSpec(IvParameterSpec).getIV();
	    byte[] encryptedTextBytes = cipher.doFinal(String.valueOf(plaintext).getBytes("UTF-8"));

	    return DatatypeConverter.printBase64Binary(encryptedTextBytes);
	}

	def decrypt(char[] encryptedText) {

	    def encryptedTextBytes = DatatypeConverter.parseBase64Binary(new String(encryptedText));
	    SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");

	    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
	    cipher.init(Cipher.DECRYPT_MODE, secretSpec, new IvParameterSpec(ivBytes));

	    def decryptedTextBytes = null;

	    try {
	        decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
	    }   catch (IllegalBlockSizeException e) {
	        e.printStackTrace();
	    }   catch (BadPaddingException e) {
	        e.printStackTrace();
	    }

	    return new String(decryptedTextBytes);

	}
}

def pbe = new PBE()
def message = "PasswordToEncrypt".toCharArray();
def cipher = pbe.encrypt(message)
def plaintext = pbe.decrypt(cipher.toCharArray())
println("Message: " + String.valueOf(message));
println("Encrypted: " + cipher);
println("Decrypted: " + plaintext);