A method is provided for implementing a security mechanism in an integrated MEMS (Micro-Electro-Mechanical-System) device having a MEMS sensor with an output register associated with a sensing operation, the integrated MEMS device being electrically coupled to a computing system programmed to perform the method. The method includes, in normal operation, reading from the output register an output of the sensing operation, and in a test mode, determining, by a processor disposed within the computing system, a random value. Determining the random value can include reading from the output register, which in the test mode or provides a value from an internal pattern generator. The method also includes determining, by the processor, a validation value, reading, by the processor, the random value stored in the output register; and determining, by the processor, whether the integrated device is valid using the validation value and the random value stored in the output register.