Attack resistant theft deterrent system

A method for theft deterrence of a vehicle comprising two or more immobilization point devices and a communication bus, the method comprising:

• each of the two or more immobilization point devices generating a random number and broadcasting their random number on a bus to all of the other two or more immobilization points, where in each of the two or more immobilization point devices retains a local copy of its own random number;
• each of the two or more immobilization point devices concatenating the local copy of its own random number with the random numbers of the other of the two or more immobilization point devices from the bus;
• from the random numbers broadcast on the bus, concatenating all of the random numbers in a predetermined sequence to form a single challenge;
• wirelessly transmitting the single challenge to a remote transponder in response to a message from the remote transponder and receiving a single response;
• each of the two or more immobilization point devices comparing the single response from the transponder to their local concatenation;
• and
• when the at least a portion of the single response from the transponder is verified against a local concatenation of an immobilization point device, then enabling a function of the immobilization point device.