Comparative Analysis of BB84 and E91 Quantum Cryptography Protocols

Abstract

In this study, the BB84 and E91 quantum cryptography protocols are comparatively analyzed. The BB84 protocol, based on the fundamental principles of quantum mechanics, enables secure key exchange and is more widely used in practice due to its simpler implementation requirements. The E91 protocol, on the other hand, theoretically provides superior security by employing the violation of Bell’s inequ- ality and entanglement, but it faces practical challenges, such as maintaining en- tangled states over long distances. The paper presents a mathematical analysis of both protocols, comparing factors such as error rates, key generation rates, and se- curity conditions. In conclusion, it is noted that while BB84 is more feasible in practical applications, E91 provides stronger theoretical security.