Magneto-electric sensor for hardware trojan detection

Inventors

Jacob, Ajey • Jaiswal, Akhilesh

Assignees

University of Southern California USC

Abstract

A sensing circuit for detecting hardware trojans in a target integrated circuit is provided. The sensing circuit includes an array of magnetic tunnel junction circuits where each magnetic tunnel junction circuit including one or more magnetic tunnel junctions. Characteristically, each magnetic tunnel junction circuit configured to provide data for and/or determine a temperature map or a current map of the target integrated circuit.

Core Innovation

A sensing circuit for detecting hardware trojans in a target integrated circuit uses an array of magnetic tunnel junction circuits. Each magnetic tunnel junction circuit includes one or more magnetic tunnel junctions and provides data for and/or determines a temperature map or a current map of the target integrated circuit. The magnetic tunnel junction circuits generate fine-grain temperature and/or current maps using an on-chip BEOL sensor grid arranged as a mesh over the target IC.

For a selected magnetic tunnel junction, each magnetic tunnel junction circuit determines a percent difference between a tunnel magnetoresistance for an off-state (RA_AP) and a tunnel magnetoresistance for an on state (RA_p). The percent difference is based on TMR-based readout with differential-amplifier sensing that produces an output voltage Vout from differential sensing of the selected magnetic tunnel junction’s off-state and on-state resistances. An optional diode-based one-way readout reduces area and leakage.

The system supports high dynamic range mapping by using telegraphic MTJs, optionally including VCMA-MTJ, cascaded with increasing energy barriers. Selection elements, including transistors or diodes, are actuated by a microprocessor that runs mapping and machine-learning algorithms, such as a neural network, to identify hardware trojans from the temperature map and/or current map.

Claims Coverage

The independent claims cover a hardware-trojan detection system and a sensing circuit that use an on-chip array of magnetic tunnel junction circuits to produce a temperature map and/or a current map. Across the independent claims, the core inventive concept includes determining percent difference based on tunnel magnetoresistance between an off-state and an on state, in electrical communication with a microprocessor for producing the maps and enabling trojan detection.

The independent claims are directed to detecting hardware trojans using an MTJ array that generates temperature and/or current maps for a target integrated circuit, where each MTJ circuit computes a percent difference between off-state and on-state tunnel magnetoresistance values, and a microprocessor system receives the sensing data to produce the maps.

Stated Advantages

Documented Applications