EuroSys 2011, day one

Posted by Derek Murray

Session 1: Data, Data, Data

Keypad: An Auditing File System for Theft-Prone Devices

The challenge is that mobile devices are prone to theft and loss, and encryption is not sufficient, because people have a habit of attaching the password to the device on a post-it, and it is vulnerable to social and hardware attack. Aim is to know what (if any) data is compromised in the event of a loss, and prevent future compromises. Solution is to force remote auditing on every file access (with encryption), by storing keys on the auditing server; this is done in the file system. File system metadata are stored on the trusted server. There are significant challenges in making this performant: caching/prefetching/preallocation are used to optimize key requests, but file creation is more challenging to optimize due to file systems semantics. Blocking filename registrations have correct semantics, but poor performance; vice versa for non-blocking registrations. To reconcile this, force a thief to use blocking semantics while allowing the user to use non-blocking semantics (as much as possible), which is based on using filenames as public keys. Second challenge is allowing disconnected access: the idea is to use multiple devices carried by the user to cross-audit file accesses, which still requires devices to hoard keys before going disconnected. - dgm36


On the road: FAST 2011

Posted by Malte Schwarzkopf

I recently had the opportunity to attend FAST (the USENIX Conference on File and Storage Technologies) in sunny San José. Despite "only" running for two days, the program was packed with presentations of interesting research papers.

Back in Cambridge, I gave a trip report (slides), and have also made my (rough, unedited -- proceed with caution) notes available.