Cryptography beyond the black-box model

10.11.2015, 14:00 – 15:00

2015/11/10 14:00-15:00

Speaker: Prof. Sebastian Faust | Location: Mornewegstraße 32 (S4|14), Room 5.3.01, Darmstadt

Organizer: Prof. Marc Fischlin


Modern cryptography analyzes the security of cryptographic algorithms using a mathematical framework based on formal security definitions and a proof-driven security analysis. To this end, an adversarial model is defined that specifies the capabilities of an attacker and describes the environment in which cryptographic algorithms are executed. The most prominent security model is the black-box model, where cryptographic algorithms are assumed to be executed in a highly idealized environment. Unfortunately, countless real-world examples illustrate that the idealized assumptions made in the black-box model cease to hold when adversaries attack cryptographic implementations. For instance, so-called side-channel adversaries are typically not covered by a black-box security analysis as they target the implementation-level, instead of breaking the mathematical properties of the cryptographic algorithm.

In recent years a growing body of research investigates whether implementation attacks can be included into the black-box model. A prominent example where the black-box security analysis has been extended to the implementation-level is for the security analysis of the so-called masking countermeasure. Masking schemes are widely used in practice to randomize the cryptographic computation thereby making physical leakage emitting from a device independent of the sensitive information. In this talk, I will present some recent results on the formal security analysis of masking schemes and show how such proofs can lead to more efficient and secure schemes.

Short Bio

I am currently an Assistant Professor at Ruhr University Bochum. Before this I was a Marie Curie fellow at EPFL in Switzerland working in the area of information security and cryptography and a Postdoc at Aarhus University with Ivan Damgaard and a PhD researcher at KU Leuven in Belgium advised by Bart Preneel. During my PhD I was particular interested in leakage resilient cryptography. In an earlier life, I was working as a business & technology consultant mainly for the financial sector, and was studying Computer Science & Business at University of Mannheim in Germany.