CS Talk
May 10, 2012
10:30 a.m., AKW 200

Host: Bryan Ford

Speaker: Ariel Feldman, Princeton
Title: Privacy and Integrity in the Untrusted Cloud

Abstract: For a myriad of user-facing applications from word processing and calendaring to social networking, cloud deployment is becoming increasingly popular. Cloud services are attractive because they offer availability, reliability, global accessibility, and convenience that desktop applications cannot match. Unfortunately, these benefits come at the cost of having to trust the service provider with the confidentiality and integrity of one’s data. Private data stored with cloud providers could be leaked to malicious outsiders and insiders or turned over to government agencies, potentially without warrants. Furthermore, a malicious or compromised cloud provider could corrupt users’ data or even equivocate, showing different users divergent views of the system’s state.

In this talk, I will present two systems that make it possible to benefit from a centralized cloud provider without having to trust it with the privacy and integrity of users’ data. In both systems, the provider’s servers see only encrypted data and cannot deviate from correct execution without detection. The first system, SPORC, allows concurrent, low-latency editing of shared state, permits disconnected operation, and supports dynamic access control even in the presence of concurrency. The second, Frientegrity, provides strong defenses against server equivocation as well as dynamic access control that scale to the demands of a large social networking service. Both of these systems explore what is possible when the confidentiality and integrity of users’ data depends on the security of their own cryptographic keys, and not on a service provider’s good intentions.

Bio: Ariel J. Feldman is a Ph.D. candidate in computer science at Princeton University whose research focuses on systems security and applied cryptography. His recent work has been aimed at developing practical cloud-based systems that protect the confidentiality and integrity of users’ data by design rather than through promises and legal contracts. Previously, he has worked on improving the security of electronic voting systems and disk encryption.