1. A diagnostic system for a hybrid vehicle, comprising: a processor module that outputs a seed value; and a motor control module that controls torque output by an electric motor of said hybrid vehicle, that receives said seed value, that performs a number of computational steps based on said seed value, that increments a counter value each time one of said computational steps is performed, that generates a final key value as a result of said computational steps, that outputs said final key value to said processor module, and that outputs said counter value to said processor module.