Antitheft system for vehicle

摘要

In a keyless entry system (100), a CPU (154) in an ECU (150) and a CPU (124) in a remote control key (120) change a function formula (F1) specified by primary function formula data (D1) stored in a memory (126) and a function formula (F1) specified by primary function formula data (D1) stored in a memory (156) to respective new function formulas (F2). With this structure, function formulas (F) used in the remote control key (120) and the ECU (150) can be changed to respective new function formulas (F). This makes it possible to enhance the safety of the keyless entry system (100) because it is difficult to predict the function formulas (F) used in the remote control key (120) and the ECU (150).