IPG Seminar: An operational approach to information leakage
Event details
| Date | 04.10.2017 |
| Hour | 16:15 › 17:00 |
| Speaker | Ibrahim Issa - LINX, EPFL |
| Location | |
| Category | Conferences - Seminars |
Abstract:
Given two random variables X and Y, how much information does Y "leak'' about X? An operational approach is undertaken to answer this fundamental question. The resulting measure L(X to Y) is called maximal leakage, and is defined as the multiplicative increase, upon observing Y, of the probability of correctly guessing a randomized function of X, maximized over all such randomized functions. A closed form expression for maximal leakage is given for discrete X and Y, and it is subsequently generalized to handle a large class of random variables. The resulting properties are shown to be consistent with an axiomatic view of a leakage measure, and the definition is shown to be robust to variations in the setup. Moreover, a variant of the Shannon cipher system is studied, in which performance of an encryption scheme is measured using maximal leakage. A single-letter characterization of the optimal limit of (normalized) maximal leakage is derived and asymptotically-optimal encryption schemes are demonstrated. Furthermore, the guessing framework is used to give operational definitions to commonly used leakage measures, such as Shannon capacity, maximal correlation, and local differential privacy. Counter-intuitively, it is shown that Shannon capacity underestimates leakage.
Bio:
Ibrahim Issa is a postdoctoral researcher at the Laboratory for Information in Networked Systems at EPFL (Lausanne, Switzerland), under the supervision of Prof. Michael Gastpar. He obtained his Ph.D in Electrical and Computer Engineering in 2017 at Cornell, Ithaca, NY, where he was also awarded the M.S. degree. He received his B.E. degree in Computer and Communications Engineering from the American University of Beirut, Lebanon, in 2012. His research interests include information-theoretic security and quantum information theory. At Cornell, he was the recipient of the ECE Outstanding Thesis Research Award (2017), and of the Jacobs fellowship (2012-2013).
Given two random variables X and Y, how much information does Y "leak'' about X? An operational approach is undertaken to answer this fundamental question. The resulting measure L(X to Y) is called maximal leakage, and is defined as the multiplicative increase, upon observing Y, of the probability of correctly guessing a randomized function of X, maximized over all such randomized functions. A closed form expression for maximal leakage is given for discrete X and Y, and it is subsequently generalized to handle a large class of random variables. The resulting properties are shown to be consistent with an axiomatic view of a leakage measure, and the definition is shown to be robust to variations in the setup. Moreover, a variant of the Shannon cipher system is studied, in which performance of an encryption scheme is measured using maximal leakage. A single-letter characterization of the optimal limit of (normalized) maximal leakage is derived and asymptotically-optimal encryption schemes are demonstrated. Furthermore, the guessing framework is used to give operational definitions to commonly used leakage measures, such as Shannon capacity, maximal correlation, and local differential privacy. Counter-intuitively, it is shown that Shannon capacity underestimates leakage.
Bio:
Ibrahim Issa is a postdoctoral researcher at the Laboratory for Information in Networked Systems at EPFL (Lausanne, Switzerland), under the supervision of Prof. Michael Gastpar. He obtained his Ph.D in Electrical and Computer Engineering in 2017 at Cornell, Ithaca, NY, where he was also awarded the M.S. degree. He received his B.E. degree in Computer and Communications Engineering from the American University of Beirut, Lebanon, in 2012. His research interests include information-theoretic security and quantum information theory. At Cornell, he was the recipient of the ECE Outstanding Thesis Research Award (2017), and of the Jacobs fellowship (2012-2013).
Practical information
- Informed public
- Free
- This event is internal
Organizer
- IPG
Contact
- olivier.leveque#epfl.ch