Quantum mechanics is the basic principle which is applied in the cryptographic scenario of quantum cryptography. Present paper provides a conceptual framework on the high level security protocol in Quantum cryptography. This is used as a base for data security through quantum computing in modern cryptosystem. In this paper first of all a detailed description of BB84 protocol with noise and without noise is explained, then a detailed description of mathematical analysis done by [1] on entropy

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... urity is also shown. Finally the result of the experimental work done on Matlab is shown. Our work reveals that at only 37 % bit of the key, we get maximum entropy security in communication network. .In this approach it is also possible to manage security as well as personalize services based on Quantum cryptography in better way.