Cascade protocol with parameters and backtracking optimization

In the quantum key distribution (QKD) process, Post-processing is one of the most important stages, Post-processing consists of four processes: Kibby right, Error rate estimation, Error code negotiation, and Private amplification. Error negotiation is the main performance bottleneck, this paper improves the Cascade protocol, optimizes parameters and backtracking process, and improves negotiation efficiency and negotiation time. The simulation results show that the negotiation efficiency and the negotiation speed are improved.