Research Of Byzantine Fault-tolerant Technology Based On Trusted Counter

Researchers have made great efforts in improving the fault tolerance of both centralized and replicated systems against arbitrary (Byzantine) faults. However, there are hard limits to how much can be done with entirely untrusted components; for example, replicated state machines cannot tolerate more than a third of their replica population being Byzantine.Recently, Chun propose Attested Append-Only Memory (A2M), a trusted system facility that is easy to implement and easy to verify formally. A2M provides the programming abstraction of a trusted log, which leads to protocol designs immune to equivocation-the ability of a faulty host to lie in different ways to different clients or servers-which is a common source of Byzantine headaches.But a trusted log requires a lot of trusted storage space, which will cause inconvenience to large-scale implementation.Instead of a trusted log,we propose a smaller trusted component which called trusted counter(TrCou),it is little more than a monotonic counter and a key.using TrCou,the A2M fault-tolerant system not only can store log in untrusted memory,but also can reduce the number of verify message among the nodes.This paper mainly does the following three work:Firstly,this paper has designed the interface functions of TrCou.TrCou is a trusted hardware module that holds a non-decreasing counter and a hidden cryptographic key,this combination can improves various aspects of security in distributed systems.Relative to A2M,TrCou has a simpler abstractions counter instead of a log.Secondly, this paper use TrCou to improve attested append-only memory(A2M) and produce a new A2M-PBFT enabled protocol:A2M-PBFT-EA and A2M-PBFT-E.Lastly,By designing relevant simulation experiment, we have verified the performance of the system. The result of the experiment show that the new A2M protocol based on TrCou has a less response time compare to the old A2M protocol.