Analyzing physical invasive fault injection techniques and designing silicon-level self-defense mechanisms.
Advanced adversaries and state-sponsored testing labs utilize active physical attacks to induce transient faults during cryptographic calculations (Differential Fault Analysis - DFA). Common techniques include localized substrate optical laser pulses, power supply voltage glitching, and rapid external clock overclocking to bypass instruction checks or force predictable mathematical errors.
HSMCryptography mitigates DFA by deploying dual-core lockstep cryptographic processors running temporally offset instructions. The outputs of both cores are compared cycle-by-cycle by hardware checking logic; any divergence immediately triggers zeroization before erroneous cryptographic results can be output to the bus.
The silicon die is crisscrossed by analog glitch detectors and optical photodiodes sensitive to infrared and green laser wavelengths used in decapsulated chip attacks. Detection of light or abnormal voltage transients triggers crowbar circuits that pull the internal power rail to ground in under 5 nanoseconds.