Cooperative Certificate Revocation List Distribution Methods in VANETs

This paper discusses two new methods for distributing certificate revocation lists (CRL) in a vehicular ad hoc network environment using cooperative methods. The main purpose for using cooperative methods is to attempt to reduce the number of collisions in the dedicated short range communication (DSRC) broadcast environment. The reduced number of collisions will increase the effective throughput of the medium. The first method uses a polling scheme to determine which nodes possess the most number of CRL file pieces. The second method takes advantage of the multiple service channels available in DSRC. Both methods use a form of coding that reduces the impact of the piece problem. Both methods are compared to the Code Torrent method of file distribution.