Growing Secure Distributed Systems from a Spore

Abstract

This paper describes the design and evaluation of Spore, a secure cloud-based file system that minimizes trust and functionality assumptions on underlying servers. Spore differs from other systems in that system relationships are formalized only through signed data objects, rather than in complicated protocols executed between clients and servers. This approach allows Spore to bootstrap a file system from a single object, providing integrity and security guarantees while storing all data as simple, immutable objects on untrusted servers. We use simulation to characterize the performance of this system, focusing primarily on the cost incurred in compensating for the minimal server support. We show that while a naive approach is quite inefficient, a series of simple optimizations can enable the system to perform well in real-world scenarios.