Marco Vassena, Computer Science and Engineering

​Verified Information Flow Control Libraries
Information Flow Control (IFC) is a principled approach to protecting the confidentiality and integrity of data in software systems. Intuitively, IFC sys- tems associate data with security labels that track and restrict flows of information throughout a program in order to enforce security. Most IFC techniques require developers to use specific programming languages and tools that require substantial efforts to develop or to adopt. To avoid redundant work and lower the threshold for adopting secure languages, IFC has been embedded in general-purpose languages through software libraries that promote security-by-construction with their API.

This thesis makes several contributions to state-of-the-art static (MAC) and dynamic IFC libraries (LIO) in three areas: expressive power, theoretical IFC foundations and protection against covert channels. Firstly, the thesis gives a functor algebraic structure to sensitive data, in a way that it can be processed through classic functional programming patterns that do not incur in security checks. Then, it establishes the formal security guarantees of MAC, using the standard proof technique of term erasure, enriched with two-steps erasure, a novel idea that simplifies reasoning about advanced programming features, such as exceptions, mutable references and concurrency. Secondly, the thesis demonstrates that the lightweight, but coarse-grained, enforcement of dynamic IFC libraries (e.g., LIO) can be as precise and permissive as the fine-grained, but heavyweight, approach of fully-fledged IFC languages. Lastly, the thesis contributes to the design of secure runtime systems that protect IFC libraries, and IFC languages as well, against internal- and external-timing covert channels that leak information through certain runtime system resources and features, such as lazy evaluation and parallelism.

The results of this thesis are supported with extensive machine-checked proof scripts, consisting of 12,000 lines of code developed in the Agda proof assistant.
​Marco Vassena belongs to the Information Security division of Computer Science and Engineering.

Opponent
Professor David Pichardie, University of Rennes, France

Grading committee
Professor Éric Tanter, University of Chile, Chile
Associate professor Ilya Sergei, Yale-NUS College, Singapore
Senior lecturer Andreas Abel, University of Gothenburg, Sweden

Category Thesis defence
Location: HB1, lecture hall, Hörsalsvägen 8, Hörsalar HB
Starts: 15 February, 2019, 10:00
Ends: 15 February, 2019, 11:00

Published: Tue 22 Jan 2019. Modified: Thu 07 Feb 2019