A trusted guard module stores one or more identifiers, each identifier uniquely identifying a respective electronic component of one or more electronic components in a circuit, wherein each electronic component is previously programmed with its respective identifier. In one embodiment, the one or more electronic components are in communication with the guard module via a test data channel. A query is sent from the guard module to one of the components via the test data channel, requesting that the queried component provide its respective identifier to the guard module. The guard module then receives a response from the queried component via the test data channel. The guard module compares the response to the stored identifier for the queried component. If the response fails to correspond to the stored identifier for the queried component, the guard module asserts an alarm condition.