code: public Packer useAES(final String passphrase, final boolean useRandomIV) throws NoSuchAlgorithmException,
  			NoSuchPaddingException {
  		initCipher();
  		initCipherIV((useRandomIV ? generateRandomIV(aesCipherLen) : getDefaultIV(aesCipherLen)),
  				(useRandomIV ? AESTYPEIV.RANDOM_IV : AESTYPEIV.FAKE_IV));
  		initCipherKey(passphrase);
  		return this;
  	}
docs: Sets he usage of "AES/CBC/PKCS5Padding" for encryption (default no)
  
  @param passphrase shared secret
  @param useRandomIV true for use randomIV (more secure, more size) or false for default IV (less secure,
  less size)
  @return
  @throws NoSuchAlgorithmException
  @throws NoSuchPaddingException