Paper Review:
Reliable Group Rekeying: A Performance Analysis

Reviewer: Jie Zhou


The secure group communications model requires an effecient rekeying mechanism. Previous approaches focus on rekeying after each join or leave. They lack the scalability and have out-of-sync problems. Besides, in these approaches, little attention has been paid to the problem of reliable transport of group rekey messages.


Instead of rekeying after each join or leave, in this paper, periodic batch rekeying is used to improve scalability and alleviate out-of-sync problems. Moreover, a rebliable rekey transport protocol based on the use of proactive FEC is presented, and the analysis of tradeoffs between bandwidth and rekey interval is provided.

Main Ideas

  • Batch rekeying can achieve much better performance.
  • Rekey transport has an eventual reliability and a soft rel-time requirement, and rekey transport workload has a sparseness property.
  • The proposed four system constraints can provide some guidelines for choosing rekey interval and determining the maximum number of users that a key server can support


    I rate the paper at 4 (significant contribution), because it does comprehensive investigations on the performance of reliable group rekeying including rekey encoding componet and reliable transfort. The authors have provided detailed analysis, made extensive simulations and obtained some good observations.


    When analyzing performance, we need to consider both the worst scenario and the average scenario.

    Open Questions

  • What is the effect of dynamic partitioning of group users?
  • Which FEC encoding scheme works better a workload with the spareness property?