No abstract

In PKI (Public Key Infrastructure), certificate revocation list (CRL) carries important information of the revoked certificates. Users need to check with this CRL frequently to make sure that the certificate in consideration is still valid and has not been revoked. In a wired network, this CRL is stored in a centralized Certificate Authority (CA) and can be accessed easily by users. However, in a mobile ad hoc network (MANET), which is characterized by its lack of infrastructure support, high node mobility, and the instability of communication links, we usually have to use multiple CAs. Users may not be able to connect to a particular CA, so distributing the latest version of CRL to all CAs becomes important. To solve this CRL distribution problem, a number of proposed solutions have been suggested. Most of these solutions are based on flooding. However, under what conditions flooding is a viable approach to distribute information in an ad hoc network has not been elaborated. In this paper, we take the first step to answer this question by simulation based on a realistic model. We identify some critical factors affecting the performance of flooding. And based on the simulation results, we provide useful insights on the minimum requirement for flooding to work smoothly in MANET.