  A Certificate Authority (CA) provides the critical authentication and
security services for Public Key Infrastructure (PKI) which are used for the
Internet and wired networks. In MANETs (wireless and ad hoc) there is an
inability to offer a centralized CA to provide these security services. Recent
research has looked to facilitate the use of CAs within MANETs through the use
of a Distributed Certificate Authority (DCA) for wireless and ad hoc networks.
This paper presents a number of different types of DCA protocols and
categorizes them into groups based on their factors and specifications. The
paper concludes by proposing the best DCA security services in terms of
performance and level of security.
