Small worlds in security systems: An analysis of the PGP certificate graph

Srdjan Čapkun, Levente Buttyán, Jean Pierre Hubaux

Research output: Contribution to conferencePaper

55 Citations (Scopus)


We propose a new approach to securing self-organized mobile ad hoc networks. In this approach, security is achieved in a fully self-organized manner; by this we mean that the security system does not require any kind of certification authority or centralized server, even for the initialization phase. In our work, we were inspired by PGP [15] because its operation relies solely on the acquaintances between users. We show that the small-world phenomenon naturally emerges in the PGP system as a consequence of the self-organization of users. We show this by studying the PGP certificate graph properties and by quantifying its small-world characteristics. We argue that the certificate graphs of self-organized security systems will exhibit a similar small-world phenomenon, and we provide a way to model self-organized certificate graphs. The results of the PGP certificate graph analysis and graph modelling can be used to build new self-organized security systems and to test the performance of the existing proposals. In this work, we refer to such an example.

Original languageEnglish
Number of pages8
Publication statusPublished - Dec 1 2002
EventProceedings New Security Paradigms Workshop 2002 - Virginia Beach, VA, United States
Duration: Sep 23 2002Sep 26 2002


OtherProceedings New Security Paradigms Workshop 2002
CountryUnited States
CityVirginia Beach, VA



  • PGP
  • Public-key management
  • Self-organization
  • Small-world gaps

ASJC Scopus subject areas

  • Computer Networks and Communications

Cite this

Čapkun, S., Buttyán, L., & Hubaux, J. P. (2002). Small worlds in security systems: An analysis of the PGP certificate graph. 28-35. Paper presented at Proceedings New Security Paradigms Workshop 2002, Virginia Beach, VA, United States.