Security Assessment of Rotation Countermeasure for Protection Against Fault Attacks

Fault attacks are topics of wide research in the field of cryptography. Adversaries can alter data by deliberately injecting faults into the cryptographic algorithm. It is crucial to design protections against fault attacks, as an adversary can take advantage of such errors to acquire sensitive information. The rotation countermeasure for the protection of keys and other sensitive data (ROCKY) is used to defend fault attacks. This framework builds on the random rotation of the internal state due to the shift-invariance property. A new approach is proposed to achieve the rotation countermeasure with minimal resource consumption. This paper covers the implementation of three distinct architectures of Subterranean 2.0 and ChaCha: one unprotected and two ROCKY-protected architectures. Subterranean 2.0 is a candidate for the NIST lightweight cryptography standardization process. ChaCha is a Salsa-20 family of stream ciphers designed to achieve high throughput. In this work, the implementation of the cipher round permutation is carried out on the field- programmable gate array (FPGA) and the timing and hardware overhead of both the unprotected and ROCKY-protected versions are discussed.