Public Key Infrastructure
A Public Key Infrastructure (PKI) represents a system of digital certificates, certificate authorities, registration authorities, a certificate management service, and X.500 directories.
A PKI verifies the identity and the authority of each party that is involved in an Internet transaction, either financial or operational, with requirements for identity verification. Examples of these transactions include confirming the origin of proposal bids, or the author of e-mail messages.
A PKI supports the use of certificate revocation lists (CRLs). A CRL is a list of revoked certificates. CRLs provide a more global method for authenticating client identity by certificate, and can verify the validity of trusted CA certificates.
An X.500 directory server stores and retrieves CRLs and trusted CA certificates. The protocols used for storing and retrieving information from an X.500 directory server include Directory Access Protocol (DAP) and Lightweight Directory Access Protocol (LDAP). The IBM® HTTP Server supports LDAP.
You can distribute information on multiple directory servers over the Internet and intranets, enabling an organization to manage certificates, trust policy, and CRLs from either a central location, or in a distributed manner. This capability makes the trust policy more dynamic because you can add or delete trusted CAs from a network of secure servers, without having to reconfigure each of the servers.