Abstract

Storage systems typically trust some amount of infrastructure to behave correctly—the network, a file server, a certificate authority. Many interpret “protecting data” to mean building a security fence around this trusted infrastructure. Unfortunately, people frequently fail to build high enough fences. Moreover, even low fences inconvenience honest people by limiting the ways in which they can access, update, and manage data.

An alternative is to design systems that cope with compromised infrastructure. This talk will present a set of techniques that progressively chip away at the security requirements of ordinary network file systems—eliminating the need to trust the network, eliminating the need to rely on certificate authorities, eliminating the need to trust replicas of popular data, mitigating the effects of compromised clients and passwords.

Finally, I’ll show how clients can detect attempts to tamper with data even after an attacker completely compromises the file server. All of these techniques have been realized in usable systems, demonstrating that practical, strong data security need not come at the cost of high fences and their associated management constraints.