Statistical GGP Game Decomposition

International audienceThis paper presents a statistical approach for the decomposition of games in the General Game Playing framework. General game players can drastically decrease game search cost if they hold a decomposed version of the game. Previous works on decomposition rely on syn-tactical structures, which can be missing from the game description, or on the disjunctive normal form of the rules, which is very costly to compute. We offer an approach to decompose single or multi-player games which can handle the different classes of compound games described in Game Description Language (parallel games, serial games, multiple games). Our method is based on a statistical analysis of relations between actions and fluents. We tested our program on 597 games. Given a timeout of 1 hour and few playouts (1k), our method successfully provides an expert-like decomposition for 521 of them. With a 1 minute timeout and 5k playouts, it provides a decomposition for 434 of them

Fair Blind Signatures without Random Oracles

International audienceA fair blind signature is a blind signature with revocable anonymity and unlinkability, i.e., an authority can link an issuing session to the resulting signature and trace a signature to the user who requested it. In this paper we first revisit the security model for fair blind signatures given by Hufschmitt and Traoré in 2007. We then give the first practical fair blind signature scheme with a security proof in the standard model. Our scheme satisfies a stronger variant of the Hufschmitt-Traoré model