Quantum-Resilient Banking Transaction Security using DW-HKEM: A Hybrid RSA/ML-KEM Cryptographic Gateway with Real-Time

Abstract

The increasing number of online banking and financial services on public-facing networks has caused security of cryptographic protocols to become a serious, systemic problem. RSA-2048 is the key length that is used in the majority of transactions that travel over the Internet every day. A very insidious threat vector, the Harvest Now, Decrypt Later (HNDL) paradigm, is already in existence with the adversarial nation-state actors and well-funded threat actors. The exposure window is not a time in the future it is the NOW moment! Quantum computation is a certain threat to the current public-key cryptographic infrastructure, and one that is moving ever closer. In this paper, the authors take up both of these challenges, designing, implementing and testing an integrated system based on a Dual-Wrap Hybrid Key Encapsulation Mechanism (DW-HKEM) and a live cryptographic analytics dashboard. Both the RSA-256 and ML-KEM-768 are hosted within the DW-HKEM framework and an AES-256 session key is wrapped in each of them, with a composite key created using a Key Derivation Function based on SHA-256, resulting in combinatorial security against classical and quantum adversaries and backwards compatibility with existing banking systems. The CryptoX real-time dashboard offers time tracking for each operation, session-level analytics and visualization of performance trends for immediate use in enterprise banking security operations. The results from empirical benchmarking across 100 independent iterations show a total overhead of about 1.58ms, which is well within the enterprise deployment threshold, proving the architecture viable as a practical, scalable reference for the financial-sector's cryptographic infrastructure and applications to move to a post-quantum era. We also provide complete source code of the work carried out.