Recently, the public key infrastructure has become increasingly import
ant for cryptographic schemes. Little research has been done, however,
on the design of public key infrastructures. Although the public key
infrastructure can be solved using the current standard X.509, it has
not proved to be efficient when the required security level is high. I
n this paper, we introduce a two-level public key infrastructure. It p
rovides a more practical and competitive application than X.509. (C) 1
998 Elsevier Science B.V.