Securely calculating and storing vehicle odometer data

In a vehicle that includes a current engine, a first electronic control unit associated with the current engine, and a second electronic control unit that is communicatively connected to the first electronic control unit, a method of calculating an official vehicle odometer value that represents a total distance traveled by the vehicle, the method comprising:

• maintaining a current engine offset in a memory of the second electronic control unit, wherein the current engine offset represents the total distance traveled by the vehicle calculated as a sum of one or more previous engine offsets and a difference between an official engine odometer value of the one or more previous engines and an engine odometer value of the current engine;
• receiving the engine odometer value from the first electronic control unit, wherein the engine odometer value represents the total distance traveled by the vehicle using the current engine;
• and
• calculating an official vehicle odometer value to determine if the engine odometer value is tampered, wherein the official vehicle odometer value is based on a summation of the engine odometer value received from the first electronic control unit and the current engine offset maintained in the memory of the second electronic control unit.