Bridging Classical and Quantum Cryptography: Evaluating BB84 and the Role of Entanglement in Secure Communication

Abstract

In the modern digital era, cryptographic protocols form the foundation of secure communication, from safeguarding messages to protecting national infrastructure. For years classical encryption techniques served the role of protecting our information; however, due to technological advancements not only in the engineering field but also in the field of physics classical encryption no longer provides reliable and safe security [2][3][4][7]. Quantum communication has introduced a fundamentally new paradigm in secure communication, most notably through the BB84 protocol [1]. This protocol uses a fundamentally different approach to security that offers unbreakable encryption [10]. The advances of the field not only offer protection but also open the possiblity to different approaches to attack [11][15]. However, despite its clear advantages, the widespread adoption of the BB84 protocol in everyday communication remains limited by technological and physical barriers [11][15]. These challenges include photon loss in transmission, limited key generation rates, short coherence of quantum states, and difficulty integrating these complex systems with existing classical infrastructures [14][17]. Furthermore, achieving scalability to support large, complex networks introduces new constraints [14]. While these systems can enable fast and long distance transmission, these technologies still remain developmental as well. This paper argues that an overlooked challenge in integrating quantum systems with classical infrastructure is the absence of entanglement in the BB84 protocol, which forces a reliance on classical components that introduce interference and instability [14][18][10]. Although the benefits of entanglement–based protocols are recognized in the literature [8][10] [19] the consequences of the BB84’s non entangled design remains underexplored [14][17][13].