Centralised​ ​ vs​ ​ Decentralised​ ​ Systems: an​ ​ Interdisciplinary​ ​ Perspective

Program​

10h00-10h30: Welcome ​ ​ Coffee

10h30-12h30: Towards​ ​ Trustworthy​ ​ Online​ ​ Voting: Distributed​ ​ Aggregation​ ​ of​ ​ Confidential​ ​ Data​ ​ (public​ ​ PhD​ ​ defense) - Robert​ ​ Riemann,​ ​ Inria​ ​ & ​ ​ ENS​ ​ Lyon

Abstract: Aggregation of values that need to be kept confidential while guaranteeing the robustness of the process and the correctness of the result is necessary for an increasing number of applications. Various kinds of surveys, such as medical ones, opinion polls, elections require the aggregation of confidential data. In general, the confidentiality is ensured on the basis of trusted third parties or promises of cryptography, whose capacities cannot be assessed without expert knowledge.

The ambition of the presented thesis is to reduce the need for trust in both authorities and technology and explore methods for large-scale data aggregations, that ensure a high degree of confidentiality and rely neither on trusted third parties nor solely on cryptography. Inspired by BitTorrent and Bitcoin, P2P protocols are considered.

The first contribution of this thesis are robustness improvements for the distributed aggregation protocol BitBallot. The encountered scalability limitations lead to the second contribution with the objective to support large-scale aggregations. Inspired by both BitBallot and BitTorrent, a novel distributed protocol called ADVOKAT is proposed.

In both protocols, peers compute pre-determined intermediate results. The partition of data and computation among a network of equipotent peers limits the potential for data breaches and reduces the need for trust in authorities. The protocols provide a middleware layer whose flexibility is demonstrated by voting and lottery applications.

12h30-14h00: Lunch ​(and ​ ​ Defense ​ ​ Fest, ​ ​ pot ​ ​ de ​ ​ thèse)

14h00-14h15: Introduction​ ​Centralised​ ​ vs​ ​ Decentralised​ ​ –a​ ​ contemporary​ ​ challenge, Stéphane​ ​ Grumbach,​ ​ Inria​ ​ & ​ ​ ENS​ ​ Lyon

14h15-14h45: Different​ ​ voting​ ​ protocols​ ​ and​ ​ their​ ​ impact​ ​ on​ ​ the​ ​ result, Antoinette​ ​ Baujard,​ ​ Université​ ​ Jean​ ​ Monnet

14h45-15h15: Jumplyn:​ ​ building​ ​ competitive​ ​ information​ ​ management​ ​ systems, Stéphane​ ​ Frénot,​ ​ INSA​ ​ Lyon

15h15-15h30: Coffee ​ ​ Break

15h30-16h00: Decentralisation​ ​ in​ ​ Practice:​ ​ Personal​ ​ Hardware​ ​ Cloud, Benjamin​ ​ Nguyen,​ ​ INSA​ ​ Centre​ ​ Val​ ​ de​ ​ Loire

16h00-16h30: Generating​ ​ System​ ​ Trust​ ​ in​ ​ Voting​ ​ Systems, Jörg​ ​ Pohle,​ ​ Humboldt​ ​ Institute​ ​ for​ ​ Internet​ ​ and​ ​ Society​ ​ (Berlin)

16h30-17h00: k-times​ ​ Full​ ​ Traceable​ ​ Ring​ ​ Signature, Pascal​ ​ Lafourcade,​ ​ Université​ ​ Clermont​ ​ Auvergne

Program (.pdf)