A comparison between Certificate Verification Tree and Certificate Revocation List shows that both of them have the same performance as a whole. An extended scheme of Certificate Verification Tree, which is completely comparable to the former two schemes, is proposed by issuing more short validity certificates to a signer at a time. And this scheme also inherits most of the advantages of the original Certificate Verification Tree. It is demonstrated that the computation time, storage requirements, and communication complexity can be allocated properly according to the specific applications in the design of PKI.