Well I began with PKI a year ago with RFID system at school. Now I'm asked to implement this in my job. I understand most part of the idea. The doubt is about the certificate validation. I know it ...
What is the benefit of having certificates expire at some fixed date?
I'm playing around with the idea of running a mini-CA with my (hobby) website, likely only used internally with a few select developers for internal emails, client authentication, staging/development ...
X.509 certificates can be used for servers, clients, email, code signing and more applications. http://twitpic.com/6gdxaq indicates that a certificate can have different of these 'capabilities' on it ...