Patent attributes
In some embodiments, a tamper-respondent system includes a PCB having a coating on a surface thereof, wherein the coating includes spinel-based, non-conductive metal oxide mixed into a non-conductive supporting material. The tamper-respondent system also includes a conductive track writing unit, a sensor, and an enclosure substantially enclosing the PCB, conductive track writing unit, and sensor. Responsive to a determination that a signal output from the sensor is indicative of tampering, the conductive track writing unit writes a conductive track within a predetermined portion of the coating by irradiating the predetermined portion of the coating to reduce the spinel-based, non-conductive metal oxide in the predetermined portion of the coating to metal nuclei. In some embodiments, the conductive track may modify circuit paths of the PCB and/or create electrical features on the PCB detectable by monitoring agents.