It is effective to use trust-management (TM) systems addressing authorization in decentralized environments. However, how to store certificates is an important and unresolved problem in this research area, which determines certificate chain discovery algorithm. In this paper, a new strategy to store certificates is put forward by using two-dimensional certificate information and Hilbert space filling curve. This strategy has not only the characteristic of load balance but also enough flexibility to search for certificates. An optimized certificates search algorithm is put forward, based on the query consisting of partial keyword. In addition to this, an algorithm to discover certificate chain is brought forward for creating the minimum certificates graph reducing the network traffic greatly.