An analysis of the eavesdropping threshold of quantum cryptography protocol

This paper establishes a channel model by analyzing various factors which affect the quantum state in the process of practical quantum communication, and derives, through calculation and simulation, a new formula for a safety threshold of eavesdropping discrimination by the BB84 Protocol. This formula can be used to estimate the safety communication threshold of the BB84 Protocol in non-ideal channels. The method for estimating the practical safety thresholds can decide more accurately whether or not eavesdropping exists in the process of quantum cipher key distribution, thus raising the safety and efficiency of communication process.