Public Key Infrastructure

We said that it is a legal requirement for public network operators to provide plaintext
access to traffic passing through the network. This is the reason for the Public Key
Infrastructure. PKI has the following three functional components (see also Figure 9.1):
Certificate Authority (CA). This is a trusted third party and might be a commercial
company such as VeriSign, Entrust, or Baltimore.
Repository Authority (RA). The RA contains the keys, certificates (information
about users), and certificate revocation lists (CRLs, which contain information
on time expired or compromised certificates).
Management function. This function looks after key recovery, message, or data
recovery.