Towards Securing ASCON Implementation by Inner Product Masking

Ascon algorithm has been selected by NIST for standardization of the lightweight cryptography, that will be used in embedded systems, IoT devices, and other resource-constrained devices. As a lightweight cryptographic algorithm, Ascon implementation requires less computation and memory. However, the current implementations of Ascon algorithms and existing protection schemes are vulnerable to side-channel attacks. In this paper, we propose an IPM (inner product masking) based protection for Ascon implementations. Our new masking scheme can prevent side-channel attacks from successfully retrieving the key, even when the leakage levels are nearly identical. Alternatively, the cost of obtaining the key can increase by several orders of magnitude, making the attack significantly more challenging. The proposed scheme is experimentally validated by porting it into a STM32F407 microcontroller and conducting correlation power analysis (CPA) and template attack (TA) on the collected power traces. The experimental results show that while CPA can successfully retrieve the keys from both the unprotected Ascon implementation and the Boolean-masked Ascon implementation, they fail against the new masking scheme. Although TA attacks can break the new scheme, they require approximately 50 times more data compared to attacking the Boolean mask. This demonstrates that the new masking scheme offers significantly greater security than both the Boolean mask and the unprotected implementations.