RITAS: Services for Randomized Intrusion Tolerance

Randomized agreement protocols have been around for more than two decades. Often assumed to be inefficient due to their high expected communication and computation complexities, they have remained overlooked by the community-at-large as a valid solution for the deployment of fault-tolerant distributed systems. This paper aims to demonstrate that randomization can be a very competitive approach even in hostile environments where arbitrary faults can occur. A stack of randomized intrusion-tolerant protocols is described and its performance evaluated under several settings in both local-area-network (LAN) and wide-area-network environments. The stack provides a set of relevant services ranging from basic communication primitives up to atomic broadcast. The experimental evaluation shows that the protocols are efficient, especially in LAN environments where no performance reduction is observed under certain Byzantine faults.