Subproject CO-PRIVACY/V-PRIVACY, led by CRISES/URV, will deal with the theory of coprivacy and the VANET application scenario. Specific objectives are:

  1. Develop a theory of coprivacy which, given a privacy preservation problem and a parameter d ? [0,1], can answer under which conditions a d-coprivate game (i.e. protocol) that solves the problem exists. b) Elaborate a theory of general coprivacy which also takes security and functionality into account. In this generalization, the Nash equilibrium that characterizes coprivacy is to be reached by considering utilities which combine the privacy with the security and/or the functionality obtained by the players. Cooperative games and strong Nash equilibria for coprivacy will also be studied. c) Elaborate a theory of mixed coprivacy to characterize when mixed strategies, and therefore mixed coprivacy, make sense for utilities about privacy, security and functionality.
  2. Create new cryptographic protocols to implement the privacy graduality needed in coprivacy. Specifically, ad hoc broadcast encryption, anonymous ad hoc broadcast encryption, (n,N)-anonymity signatures and some multiparty computation protocols for social networks are needed.
  3. Model VANET communication as a generally coprivate game, involving a trade-off between functionality and privacy. b) Adapt the general utility functions developed in the theoretical objectives to the case of VANET communication, so that coprivacy can be verified. c) To make general coprivacy between functionality and privacy compatible with security, design privacy technologies for VANETs with the novel feature of allowing gradual privacy. (n,N)-anonymity signatures will be designed, whereby a driver can choose to hide herself into any n-member group of the overall N-member group. In addition to graduality, (n, N)-anonymity should have all the above-mentioned properties of our MLGS signatures, which we view as the special case where N = n.


  • Jordi Aragončs
  • Dr. Jordi Castellŕ
  • Dr. Josep Domingo-Ferrer, principal investigator (PI) of the subproject and CO-PRIVACY co-ordinator
  • Arnau Erola
  • Dr. Oriol Farrŕs
  • Dr. Josep M. Gastó
  • Sara Hajian
  • Roger Jardí
  • Jesús Manjón
  • Dr. Antoni Martínez
  • Dr. Josep M. Mateo
  • Dr. Cčsar Mauri
  • Pau Pérez
  • Dr. Jordi Pujol
  • Cristina Romero
  • Dr. Agustí Solanas
  • Jordi Soria
  • Rolando Trujillo
  • Dr. Alexandre Viejo