(1) Trace the identity of information transmission.

(2) The privacy of information.

(3) An unforgeable signature.

(4) Rules for sending information.

Byzantine failure is a basic problem in point-to-point communication proposed by Leslie Lambert. This means that it is impossible to try to achieve consistency through message delivery on unreliable channels with message loss. Byzantine hypothesis is a model of the real world. Due to hardware errors, network congestion or disconnection, and malicious attacks, computers and networks may have unpredictable behaviors.