POSTER: DataLair: A Storage Block Device with Plausible Deniability

Abstract

Sensitive information is present on our phones, disks, watches and computers. Its protection is essential. Plausible deniability of stored data allows individuals to deny that their device contains a piece of sensitive information. This constitutes a key tool in the fight against oppressive governments and censorship. Unfortunately, existing solutions, such as the now defunct TrueCrypt [2], can defend only against an adversary that can access a user's device at most once ("single-snapshot adversary"). Recent solutions have traded significant performance overheads for the ability to handle more powerful adversaries able to access the device at multiple points in time ("multi-snapshot adversary"). In this paper we show that this sacrifice is not necessary. We introduce and build DataLair, a practical plausible deniability mechanism. When compared with existing approaches, DataLair is two orders of magnitude faster (and as efficient as the underlying raw storage) for public data accesses, and 3-5 times faster for hidden data accesses. An important component in DataLair is a new, efficient write-only ORAM construction, which provides an improved access complexity when compared to the state-of-the-art.