Vassilios Lekakis

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CONCLUSIONS • Current protocols, in a multiuser setting, leak information • Security should be a major building block of personal data management systems • Elimination of leakage through: • Role-based access control • Object forking • Role-based consistency OBJECT FORKING • No information leakage between intersecting roles • Storage overhead due to multiple(More)
We introduce Accountable Storage (AS), a framework allowing a client with small local space to outsource n file blocks to an untrusted server and be able (at any point in time after outsourcing) to provably compute how many bits have been discarded by the server. Such protocols offer " provable storage insurance " to a client: In case of a data loss, the(More)
A " home " sharing environment consists of the data sharing relationships between family members, friends, and acquaintances. We argue that this environment, far from being simple, has sharing and trust relationships as complex as any general-purpose network. Such environments need strong access control and privacy guarantees. We show that avoiding(More)
—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(More)
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