Actuating a security system includes providing a first set of access codes to a wireless device and causing the wireless device to transmit the first set of access codes to a first controller that actuates the security system. The first set of access codes provided to the wireless device may expire. Actuating a security system may also include providing expiration dates for each of the first set of access codes provided to the wireless device. Actuating a security system may also include examining each of the expiration dates and, in response to a particular expiration date being prior to a current date, erasing from the wireless device a particular one of the first set of access codes that corresponds to the particular expiration date.