Certificate Path Verification in Hierarchical and Peer-to-Peer Public Key Infrastructures

“Authentication of users in an automated business transaction is commonly realized by means of a Public Key Infrastructure(PKI). A PKI is a framework on which the security services are built. Each user or end entity is given a digitally signed data structure called digital certificate. In Hierarchical PKI, certificate path is unidirectional, so certificate path development and validation is simple and straight forward. Peer-to-Peer(also called Mesh PKI) architecture is one of the most popular PKI trust models that is widely used in automated business transactions, but certificate path verification is very complex since there are multiple paths between users and the certification path is bidirectional. In this paper, we demonstrate the advantage of certificate path verification in Hierarchical PKI based on forward path construction method over reverse path construction method with respect to the time requirement. We also propose a novel method to convert a peer-to-peer PKI to a Depth First Search(DFS) spanning tree to simplify the certificate path verification by avoiding multiple paths between users, since the DFS spanning tree equivalent of peer-to-peer PKI contains only one path between any two Certification Authorities.