Quantum Readiness in Cryptography: A Maturity-Based Framework for Post-Quantum Transition

Quantum computing poses an existential threat to public-key cryptography, with Shor's algorithm capable of breaking RSA and elliptic curve systems once cryptographically relevant quantum computers (CRQCs) emerge. While post-quantum cryptography (PQC) offers algorithmic solutions, organizational readiness extends beyond technical implementation to encompass governance, interoperability, and adaptive capacity. This review synthesizes the quantum threat landscape, evaluates NIST-standardized PQC algorithms through quantitative performance analysis, and examines global standardization dynamics. We introduce a novel Quantum Readiness Maturity Model (QRMM) that enables organizations to assess and advance their preparedness across five dimensions: cryptographic infrastructure, governance frameworks, sectoral adaptation, interoperability resilience, and strategic agility. Applying this model to finance, telecommunications, and defense sectors reveals systematic gaps in migration planning and crypto-agility. Our analysis demonstrates that quantum readiness requires treating cryptographic transformation as a strategic enterprise capability rather than a purely technical upgrade. The proposed framework provides actionable pathways for practitioners while identifying critical research directions in hybrid deployment strategies, post-quantum PKI architectures, and algorithmic diversity.