Post-Quantum Migration Strategies: A Hybrid Approach to Cryptographic Transition Authors

Hridoy Roy

Arinze Mba, Idahosa Emmanuel

Quantum computing presents a long-term challenge to the cryptographic foundations that secure modern digital financial systems. While significant progress has been made in post-quantum cryptographic standardisation, practical migration remains a complex challenge involving operational continuity, governance requirements, regulatory obligations, infrastructure dependencies, and performance constraints. This research proposes a Governance-Aware Post-Quantum Cryptographic Migration Framework designed for digital financial infrastructures operating within emerging and resource-constrained environments. The framework introduces adaptive migration orchestration principles that integrate governance enforcement, hybrid cryptographic transition strategies, performance-aware migration zones, and formal migration-state abstractions capable of supporting future verification activities. Unlike traditional migration approaches that focus primarily on cryptographic replacement and interoperability, the proposed framework treats post-quantum migration as a controlled systems transition process requiring coordination between security objectives, compliance requirements, operational resilience, and infrastructure readiness. The work contributes a hybrid cryptographic state-transition model, governance-aware migration control mechanisms, performance-constrained migration orchestration principles, and a TLA⁺-ready formal migration abstraction intended to support future validation of migration safety, governance consistency, and operational stability. This manuscript is intended as a research contribution toward practical and scalable post-quantum migration strategies for financial ecosystems preparing for the transition to quantum-resilient security architectures.

Stefan-Lukas Gazdag

Subhajit Roy

This preprint presents a systems-security and architectural analysis of post-quantum cryptography deployment challenges in modern API ecosystems. The paper examines hybrid TLS 1.3 integration, cryptographic agility, migration strategies, API gateway architectures, certificate management, and operational considerations surrounding quantum-resilient distributed systems. The work focuses on applied cryptographic engineering and migration planning rather than proposing new cryptographic primitives. It synthesizes current standards, adversarial models, implementation constraints, and deployment considerations relevant to practical post-quantum migration for API infrastructure. Keywords: post-quantum cryptography, API security, TLS 1.3, ML-KEM, cryptographic agility, hybrid TLS.

Hillary Muzenda, Belinda Mutunhu Ndlovu

Quantum computing threatens the classical cryptographic systems underpinning financial infrastructure, exposing payment platforms, interbank networks, and digital services to Harvest-Now-Decrypt-Later (HNDL) risks. This study systematically reviews quantum threats and post-quantum cryptographic readiness in the financial sector to assess preparedness, identify implementation challenges, and synthesize migration pathways aligned with emerging standards. A PRISMA-guided review of 17 peer-reviewed studies published between 2020 and 2025 was conducted, examining quantum threat models, post-quantum cryptographic schemes, quantum key distribution architectures, and sector-specific deployment barriers. The review finds that lattice-based schemes, especially CRYSTALS-Kyber and CRYSTALS-Dilithium, are the leading candidates for financial adoption, while hybrid cryptographic approaches offer the most feasible transition strategy. However, the current evidence base is predominantly simulation-driven, with limited real-world deployment and validation. The study provides a sector-specific synthesis of quantum threats, post-quantum readiness, and migration pathways in financial systems, and advances an integrated readiness and migration framework based on cross-study thematic analysis.