Balancing Quantum and Classical Security: Side-Channel Challenges in NIST PQC Finalist

As quantum computing presents a known threat to classical cryptographic systems, the design of post-quantum cryptography (PQC) has been essential. Although NIST PQC finalists are specifically designed to resist quantum attacks, their susceptibility to side-channel attacks (SCAs) is still an important issue. This work analyzes the susceptibility of lattice-based, code-based, and hash-based PQC schemes against SCAs, such as power analysis, timing attacks, and fault injection. Lattice-based schemes are vulnerable to power attacks and fault injections, whereas code-based schemes are vulnerable to timing attacks. Most SCAs are mitigated in hash-based schemes however they are prone to a fault injection attack. Various countermeasures including masking, constant-time computation, and fault detection techniques are discussed, with their strengths and performance penalty emphasized. Some of the identified challenges include the lack of hardware agnostic countermeasures, hardware specific vulnerabilities. The future research directions are calling for efficient, hardware-agnostic standards to establish the practical security of PQC algorithms. Successfully overcoming such challenges ensures that the transition to PQC will not need to sacrifice resistance to both quantum and classical attacks.