CSE Colloquium: Dimitrios Papadopoulos

Title: Believing without Seeing: Cryptographic Integrity Guarantees in Outsourced Computation

Abstract: An integral component of modern computing is the ability to outsource data and computation to powerful remote servers. But this model of interaction also introduces new security issues, as one’s data no longer resides within their “zone of trust”. In particular, how can a party be assured that an outsourced computation was performed correctly by the remote server?

I will discuss cryptographic protocols that achieve integrity of computation. These protocols accompany each computation with a short and efficiently verifiable proof of correctness. Existing constructions in the literature typically come in two flavors: general-purpose schemes that can verify any computation but entail very high overheads for the server, and function-specific schemes that are more efficient, but only target limited functionalities. My approach takes the best of both worlds: I use function-specific schemes as building blocks, and compose these building blocks by leveraging ideas from the general-purpose approaches. This results in constructions that enjoy the low overheads of function-specific schemes, while providing significantly more expressiveness. Finally, I will show that the problem of securing the domain name system (DNS) is at its core a problem of integrity of outsourced computation, and present our design and implementation of NSEC5, a proposal for augmenting the security of DNS.

Bio: Dimitrios Papadopoulos is a PhD candidate in the Computer Science Department of Boston University, and a member of the BU Security Group. He received his Diploma in Applied Mathematics in 2010 from the National Technical University of Athens, Greece. He has worked as a research intern at IBM Zurich and Verisign Labs. His research interests are on applied cryptography, network security, and secure cloud computing.