Аннотация
This article is about studying how strong the E91 quantum key distribution protocol is. The protocol uses the ideas of quantum mechanics. Quantum cryptography is a very hopeful field in keeping information safe, and the E91 protocol is seen as one of the most hopeful ways to guarantee complete and certain secure transmission of data. The aim of the study is to find weaknesses in the E91 protocol and understand how well it can withstand different kinds of quantum attacks. This work uses math and computer simulations to carefully study and make sure the protocol is secure. The literature review discusses previous studies on quantum cryptography and protocols for distributing keys. This study will help make better E91 protocols and will be important for keeping information safe in modern communication systems. These discoveries can help make quantum cryptography better and more useful in real-life situations. It can secure data by protecting it from increasing cyber-attacks and make sure that information systems work well.