AESEncryption

AESEncryption.java

import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

public class AESEncryption {

	private static final SecureRandom random = new SecureRandom();
	private static final String ALGORITHM = "AES";

	public static byte[] encrypt(String key, byte[] data) throws IOException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
		return AESEncryption.crypt(Cipher.ENCRYPT_MODE, key, data);
	}
	
	public static byte[] decrypt(String key, byte[] input) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, IOException {
		return AESEncryption.crypt(Cipher.DECRYPT_MODE, key, input);
	}

	private static byte[] crypt(int cipherMode, String key, byte[] input) throws IOException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
		Key secretKey = new SecretKeySpec(key.getBytes(), ALGORITHM);
		Cipher cipher = Cipher.getInstance(ALGORITHM);
		cipher.init(cipherMode, secretKey);
		return cipher.doFinal(input);
	}

	public static String generateKey() {
		int length = 16;
		String alphanumeric = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
		StringBuilder stringBuilder = new StringBuilder(length);
		for (int index = 0; index < length; index++) {
			stringBuilder.append(alphanumeric.charAt(AESEncryption.random.nextInt(alphanumeric.length())));
		}
		return stringBuilder.toString();
	}

}