Performance optimizations for certificate revocation

Certificate revocation is an outstanding problem in PKI. This paper extends Naor's scheme of dynamic hash tree in order to optimize performance. Set of revoked certificates is divided into groups. In each group, proofs for certificate status are computed by using one-way accumulator, while all groups are still organized in hash tree. The main advantage of the proposed scheme is that it can adjust traffic between CA-to-directory and directory-to-user according to certificate update rate and query rate in applications, thus can remarkably reduce overall traffic consumed for certificate revocation, and can efficiently accommodate a wide range of scenarios. Compared with Naor's origin scheme, performance analysis shows it can reduce traffic by about 50% in typical environments.