Hackaday

Researchers developed an affordable time-domain reflectometry system for tamper detection in high-security devices. The system sends sharp pulses through protective circuit meshes and times returning echoes to create fingerprints, detecting physical intrusions when new echoes appear from damaged traces. Built around an STM32G4 microcontroller with sub-200 picosecond timer resolution and HDMI redriver chips for pulse amplification, the design achieves high sensitivity at low cost, detecting even oscilloscope probe contact and temperature changes. While not impossible to bypass, defeating it requires significant skill and specialized equipment like non-conductive drill bits.

Tamper Detection With Time-Domain Reflectometry

<p>Do what Compaq did in the 90s, the computer case could be removed by sliding the top from the bottom panel, but the panels had magnets sliding over the HDD and motherboard, rendering some of the components useless if non-service personnel opened it.</p>
