Efficient and DoS-resistant Consensus for Permissioned Blockchains

Existing permissioned blockchain systems designate a fixed and explicit group of committee nodes to run a consensus protocol that confirms the same sequence of blocks among all nodes. Unfortunately, when such a permissioned blockchain runs on a large scale on the Internet, these explicit committee nodes can be easily turned down by denial-of-service (DoS) or network partition attacks. Although recent studies proposed scalable BFT protocols that run on a larger number of committee nodes, these protocols’ efficiency drops dramatically when only a small number of nodes are attacked. In this paper, we propose a novel protocol named EGES that leverages hardware trusted execution environments (e.g., Intel SGX) to develop a new abstraction called “stealth committee”, which effectively hides a committee into a large pool of fake committee nodes. EGES selects a different stealth committee for each block and confirms the same blocks among all nodes with overwhelming probability. Our evaluation shows that EGES is the first efficient permissioned blockchain's consensus protocol, which simultaneously satisfies two important metrics: (1) EGES can tolerate tough DoS and network partition attacks; and (2) EGES achieves comparable throughput and latency as existing fastest permissioned blockchains’ consensus protocols. EGES's source code is available on http://github.com/hku-systems/eges.