A master/slave data communication system in which a master device communicates with the slave devices by uniquely addressing each of the slave devices. In order to enhance the security of the data communication system, each slave device includes an address generator for generating unique addresses. Periodically, the master device requests that one or more slave device change its address. In response to the request, the addressed slave device increments its address generating algorithm to provide a new slave address. The master device also includes an algorithm that is synchronized with the slave address generating algorithm, whereby when the slave changes its address, it need not transmit the new slave address to the master device over the bus.