Understanding Public-Key Infrastructure: Concepts, Standards, and Deployment Considerations

Off-Line Operations

An architectural decision that must be made with respect to PKI deployment concerns the on-line/off-line requirements of PKI operation: Must users of the PKI be on-line to function, or is off-line operation permissible? This decision is important because it must be recognized that at least some members of the user population will be disconnected from the network on occasion (for example, while traveling). Are these users then simulta-neously disconnected from all PKI services, or is some (perhaps limited) functionality still available to them?

Note that this is largely a function of the applications being employed in the environment. Some applications require real-time connectivity (and so users must be on-line); others are ...