RAD-FS: Remote Timing and Power SCA Security in DVFS-augmented Ultra-Low-Power Embedded Systems

High-performance crypto-engines have become crucial components in modern System-On-Chip (SoC) architectures across platforms, from servers to edge-IoTs’. Alas, their secure operation faces a significant obstacle caused by information-leakage accessed through Side-Channel Analysis (SCA). Adversaries exploit statistical-analysis techniques on measured (e.g.,) power and timing signatures generated during (e.g.,) encryption, extracting secrets. Mathematical countermeasures against such attacks often impose substantial power-performance-area overheads. Dynamic Voltage and Frequency Scaling (DVFS) techniques provide power-efficiency by varying power consumption according to workload; these modulations are called power-states. Unintentionally, DVFS introduces new inherent weaknesses exploitable by malicious actors: power-states leak information in both power and timing side-channels, measurable in software and hardware. We introduce a method to increase side-channel resistance using integrated voltage regulators and DVFS: (1) Pushing known prior-art in the topic to Ultra Low Power (ULP) regime (2) For the first time introducing a mechanism to aid in counteracting the inherent weakness of DVFS in SCA (3) Providing measurements performed on 40 nm process ULP PLS15 test-chip down at 580 mV power-supply (4) Offering improved and parameterized resistance to remote -timing vulnerabilities inherent to DVFS. We present various results and perform a detailed analysis while comparing performance and security to prior-art. Importantly, our solution is configurable in terms of security, maintaining degrees-of-freedom for power-optimization of DVFS.