SYNFI: Pre-Silicon Fault Analysis of an Open-Source Secure Element

Fault attacks are active, physical that an adversary can leverage to alter the control-flow of embedded devices gain access sensitive information or bypass protection mechanisms. Due severity these attacks, manufacturers deploy hardware-based fault defenses into security-critical systems, such as secure elements. The development countermeasures is a challenging task due complex interplay circuit components and because contemporary design automation tools tend optimize inserted structures away, thereby defeating their purpose. Hence, it critical rigorously verified post-synthesis. Since classical functional verification techniques fall short assessing effectiveness (due being analyzed when no faults present), developers have resort methods capable injecting in simulation testbench chip sample. However, developing test sequences inject error-prone performing on requires specialized equipment incredibly time-consuming. Moreover, identifying fault-vulnerable hard both approaches, fixing potential flaws post-silicon usually infeasible since would require another tape-out. To end, this paper introduces SYNFI, formal pre-silicon framework operates synthesized netlists. SYNFI be used analyze general effect input-output relationship its countermeasures, thus enables hardware designers assess verify systematic semi-automatic way. automatically extracts parts circuit, induces extracted subcircuit, analyzes faults’ effects using methods. demonstrate handling unmodified, industry-grade netlists with commercial open tools, we OpenTitan, first opensource element. In our analysis, identified security weaknesses unprotected AES block, developed targeted reassessed security, contributed back OpenTitan project. For other fault-hardened IP, life cycle controller, confirm existing provide adequate protection.