A Language-Based Approach to Secure Quorum Replication

Quorum replication is an important technique for building distributed systems because it can simultaneously improve both the integrity and availability of computation and storage. Information flow control is a well-known method for enforcing the confidentiality and integrity of information. This paper demonstrates that these two techniques can be integrated to simultaneously enforce all three major security properties: confidentiality, integrity and availability. It presents a security-typed language with explicit language constructs for supporting secure quorum replication. The dependency analysis performed by the type system of the language provides a way to formally verify the end-to-end security assurance of complex replication schemes. We also contribute a new multilevel timestamp mechanism for synchronizing code and data replicas while controlling previously ignored side channels introduced by such synchronization.