Study On B92 & EPR Quantum Cryptography

Quantum key distribution is one of the core parts of quantum communication, which is one of the research hotspots of information age. And it provides a new way for transmitting message securely. Many researches on quantum communication have been done both in theory and experiment. A lot of any scientists are participating in the studies in this field.My study involves two areas in quantum key distribution protocol. First, in the field of the B92 protocol, it is first calculated and analyzed for the Holevo upper bound of B92 protocol to noise and eavesdropping, the fidelity, a lower bound on the guaranteed privacy and the capacity for classical information over phase flip channels. It is computed and validated for that projective measurements increase quantum entropy . It is analyzed for the transformation of the quantum state through projective measurements. And they can be visually contrasted relatively with the computer simulation graphics. Second, in the field of the EPR protocol, the fundamental principles of quantum teleportation of complex system based on EPR pairs are reviewed, along with non-locality, Bell basis testament and entanglement characteristics.