A Constant-Time Implementation Methodology for Activation Functions on Microcontrollers
Embedded neural-network inference can leak information through timing side channels, including leakage caused by the evaluation of activation functions. This work proposes a constant-time implementation methodology for activation functions on embedded microcontrollers and validates it on ReLU, sigmoid, tanh, GELU, and Swish on an ARM Cortex-M4 platform. The proposed methodology combines branchless selection, fixed-cost Padé-based approximation, dummy arithmetic where needed, and cycle alignment to obtain timing-regular activation-function implementations. As motivation, we also evaluate a desynchronization-based countermeasure and show that it remains vulnerable to a template-based timing...
| Authors | Andrii Tyvodar, Andreas Rechberger, Dirmanto Jap et al. |
|---|---|
| Primary category | cs.CR |
| Published | 21 May 2026 |
| Last updated at source | 21 May 2026 |
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