A system or method may include an in-vehicle network including an interface port for connecting an external device to the in-vehicle network; and a security unit connected to the in-vehicle network, the security unit adapted to enable an external device to communicate with the in-vehicle network, over the interface port, based on a security token received from the external device. A system or method may, based on a token, prevent an external device from at least one of: communicating with a selected set of components on in an in-vehicle network, communicating with a selected set of network segments in the in-vehicle network and performing a selected set of operations.