ChaCha20Poly1305 Encryption in Java11

ChaCha20Poly1305.java

package chaCha20Poly1305Encryption;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;
import java.util.Base64;

public class ChaCha20Poly1305 {

    public static byte[] encrypt(byte[] data, SecretKey key) throws NoSuchPaddingException, NoSuchAlgorithmException,
            InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        if(key == null) throw new InvalidKeyException("SecretKey must NOT be NULL");

        byte[] nonceBytes = new byte[12];

        // Get Cipher Instance
        Cipher cipher = Cipher.getInstance("ChaCha20-Poly1305/None/NoPadding");

        // Create IvParamterSpec
        AlgorithmParameterSpec ivParameterSpec = new IvParameterSpec(nonceBytes);

        // Create SecretKeySpec
        SecretKeySpec keySpec = new SecretKeySpec(key.getEncoded(), "ChaCha20");

        // Initialize Cipher for ENCRYPT_MODE
        cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivParameterSpec);

        // Perform Encryption
        return cipher.doFinal(data);
    }

    public static byte[] decrypt(byte[] cipherText, SecretKey key) throws Exception {
        if(key == null) throw new InvalidKeyException("SecretKey must NOT be NULL");
        byte[] nonceBytes = new byte[12];

        // Get Cipher Instance
        Cipher cipher = Cipher.getInstance("ChaCha20-Poly1305/None/NoPadding");

        // Create IvParamterSpec
        AlgorithmParameterSpec ivParameterSpec = new IvParameterSpec(nonceBytes);

        // Create SecretKeySpec
        SecretKeySpec keySpec = new SecretKeySpec(key.getEncoded(), "ChaCha20");

        // Initialize Cipher for DECRYPT_MODE
        cipher.init(Cipher.DECRYPT_MODE, keySpec, ivParameterSpec);

        // Perform Decryption
        return cipher.doFinal(cipherText);
    }

    public static void main(String[] args) throws Exception {
        SecretKey key = ChaCha20Poly1305KeyGenerator.generateKey();

        String testMessage = "hallo!";
        byte[] encryptedBytes = encrypt(testMessage.getBytes(), key);
        String decryptedMessage = new String(decrypt(encryptedBytes,key));
        System.out.println("testMessage: " + testMessage);
        System.out.println(key.getAlgorithm() + " SecretKey: " + Base64.getEncoder().encodeToString(key.getEncoded()));
        System.out.println("encryptedBytes: " + Base64.getEncoder().encodeToString(encryptedBytes));
        System.out.println("decryptedMessage: "+ decryptedMessage);

    }
}

ChaCha20Poly1305KeyGenerator.java

package chaCha20Poly1305Encryption;

import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;

public class ChaCha20Poly1305KeyGenerator {
    public static SecretKey generateKey() throws NoSuchAlgorithmException {
        KeyGenerator keyGenerator = KeyGenerator.getInstance("ChaCha20");
        //Keysize MUST be 256 bit - as of Java11 only 256Bit is supported
        keyGenerator.init(256);
        return keyGenerator.generateKey();
    }
    public static void main(String[] args) throws NoSuchAlgorithmException {
        SecretKey key = generateKey();
        System.out.println(key.getAlgorithm() + " SecretKey: " + Base64.getEncoder().encodeToString(key.getEncoded()));
    }
}