* @throws NoSuchAlgorithmException
*/
public byte[] encrypt(String mobileNumber, byte[] message) throws SMSLibException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, NoSuchPaddingException, NoSuchAlgorithmException
{
AKey k = getKey(mobileNumber);
if (k == null) throw new SMSLibException("Could not find Encryption Key for the specific number.");
else if (k instanceof ASymmetricKey) return ((ASymmetricKey) k).encrypt(message);
else return new byte[0];
}