import java.security.GeneralSecurityException;

import javax.crypto.Cipher;

import javax.crypto.spec.SecretKeySpec;

import com.citi.simpliciti.tempest.TempestRuntimeException;

public class AdvancedEncryptionStandard {

  private static final String ALGORITHM = "AES";

  private final SecretKeySpec secretKey;

  private final Cipher encoder;

  private final Cipher decoder;

  public AdvancedEncryptionStandard(byte[] key) {

    try {

      secretKey = new SecretKeySpec(key, ALGORITHM);

      encoder = Cipher.getInstance(ALGORITHM);

      encoder.init(Cipher.ENCRYPT_MODE, secretKey);

      decoder = Cipher.getInstance(ALGORITHM);

      decoder.init(Cipher.DECRYPT_MODE, secretKey);

    } catch (Exception e) {

      throw new TempestRuntimeException(e);

    }

  }

  /**

   * Encrypts the given plain text

   *

   * @param plainText The plain text to encrypt

   * @throws GeneralSecurityException

   */

  public byte[] encrypt(byte[] plainText) throws GeneralSecurityException {

    synchronized (encoder) {

      return encoder.doFinal(plainText);

    }

  }

  /**

   * Decrypts the given byte array

   *

   * @param cipherText The data to decrypt

   * @throws GeneralSecurityException

   */

  public byte[] decrypt(byte[] cipherText) throws GeneralSecurityException {

    synchronized (decoder) {

      return decoder.doFinal(cipherText);

    }

  }

}