A Faster Cryptographer's Conspiracy Santa - Université Clermont Auvergne Accéder directement au contenu
Article Dans Une Revue Theoretical Computer Science Année : 2020

A Faster Cryptographer's Conspiracy Santa

Résumé

In Conspiracy Santa, a variant of Secret Santa, a group of people offer each other Christmas gifts, where each member of the group receives a gift from the other members of the group. To that end, the members of the group form conspiracies, to decide on appropriate gifts, and usually divide the cost of each gift among all participants of that conspiracy. This requires to settle the shared expenses per conspiracy, so Conspiracy Santa can actually be seen as an aggregation of several shared expenses problems. First, we show that the problem of finding a minimal number of transaction when settling shared expenses is NP-complete. Still, there exist good greedy approximations. Second, we present a greedy distributed secure solution to Conspiracy Santa. This solution allows a group of n people to share the expenses for the gifts in such a way that no participant learns the price of his gift, but at the same time notably reduces the number of transactions to 2 · n + 1 with respect to a naïve aggregation of n · (n − 2). Furthermore, our solution does not require a trusted third party, and can either be implemented physically (the participants are in the same room and exchange money using envelopes) or, over Internet, using a cryptocurrency.
Fichier principal
Vignette du fichier
main.pdf (276.81 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-02611751 , version 1 (18-05-2020)

Identifiants

Citer

Xavier Bultel, Jannik Dreier, Jean-Guillaume Dumas, Pascal Lafourcade. A Faster Cryptographer's Conspiracy Santa. Theoretical Computer Science, 2020, 839, pp.122-134. ⟨10.1016/j.tcs.2020.05.034⟩. ⟨hal-02611751⟩
366 Consultations
209 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More