Introduction
The standardization of post-quantum cryptography (PQC) by the National Institute of Standards and Technology (NIST) represents a fundamental shift in cryptographic primitives deployed across global digital infrastructure. As of 2025-2026, four algorithms have reached final standardization status: FIPS 203 (CRYSTALS-Kyber/ML-KEM) for key encapsulation, FIPS 204 (CRYSTALS-Dilithium/ML-DSA) for digital signatures, FIPS 205 (SPHINCS+/SLH-DSA) for stateless hash-based signatures, and FALCON (FN-DSA) as an additional signature standard. While these algorithms provide mathematical security against quantum attacks, their implementation on physical hardware introduces new side-channel vulnerabilities distinct from classical cryptography. This article examines the implementation security landscape, documented attacks, countermeasures, and deployment timelines.