Improving Independence of Failures in BFT

Ali Shoker (1) , Jean-Paul Bahsoun (1, 2) , Maysam Yabandeh (3)

1 IRIT-SEPIA - Système d’exploitation, systèmes répartis, de l’intergiciel à l’architecture
2 UT3 - Université Toulouse III - Paul Sabatier
3 QCRI - Qatar Computing Research Institute

Independence of failures is a basic assumption for the correctness of BFT protocols. In literature, this subject was addressed by providing N-version like abstractions. Though this can provide a good level of obfuscation against semantic- based attacks, if the replicas know each others identities then non-semantic attacks like DoS can still compromise all replicas together. In this paper, we address the obfuscation problem in a different way by keeping replicas unaware of each other. This makes it harder for attackers to sneak from one replica to another and reduces the impact of simultaneous attacks on all replicas. For this sake, we present a new obfuscated BFT protocol, called OBFT, where the replicas remain unaware of each other by exchanging their messages through the clients. Thus, OBFT assumes honest, but possibly crash-prone clients. We show that obfuscation in our context could not be achieved without this assumption, and we give possible applications where this assumption can be accepted. We evaluated our protocol on an Emulab cluster with a wide area topology. Our experiments show that the scalability and throughput of OBFT remain comparable to existing BFT protocols despite the obfuscation overhead.

Mots clés: BFT; Independence of failures; Obfuscated BFT

Domaines: Réseaux et télécommunications [cs.NI]; Système d'exploitation [cs.OS]; Architectures Matérielles [cs.AR]; Systèmes embarqués

Ali Shoker, Jean-Paul Bahsoun, Maysam Yabandeh. Improving Independence of Failures in BFT. 12th IEEE International Symposium on Network Computing and Applications (NCA 2013), Aug 2013, Cambridge, MA, United States. pp.227-234. ⟨hal-01240714⟩