Marco Gaboardi
University of Pennsylvania, Department of Computer and Information Science

Linear Dependent Types for Differential Privacy

Differential privacy offers a way to answer queries about sensitive information while offering strong, provable privacy guarantees.  Several tools have been developed for certifying that a given query is differentially private. In one approach, Reed and Pierce[31] proposed a functional programming language, Fuzz, for writing differentially private queries. Fuzz uses linear types to track sensitivity, as well as a probability monad to express randomized computation; it guarantees that any program that has a certain type is differentially private. Fuzz can successfully verify many useful queries. However, it fails when the analysis depends on values that are not known statically.

We present DFuzz, an extension of Fuzz with a combination of linear indexed types and lightweight dependent types. This combination allows a richer sensitivity analysis that is able to analyze a larger class of queries, including queries whose sensitivity depends on runtime information. As in Fuzz, the differential privacy guarantees follows directly from the soundness theorem for the type system. We demonstrate the enhanced expressivity of DFuzz by certifying differential privacy a broad class of iterative algorithms that could not be typed previously.

Marco Gaboardi is currently a Marie Curie Fellow at the University of Pennsylvania and at the UniversitÓ di Bologna (Italy) in the INRIA Focus team. Previously, he held postdoc positions at the UniversitÓ di Bologna and at the UniversitÓ di Torino (Italy). He received his Ph.D. in Computer Science from UniversitÓ di Torino and Institut national polytechnique de Lorraine (France) in 2007.
His research is centered on the use of logic and type theory in the settings of implicit computational complexity, differential privacy and computation over streams.


Host: Frank Pfenning

Monday, October 29, 2012
2:30 p.m.
Gates & Hillman Centers - 6115

Principles of Programming Seminars