certmonger is a service which attempts to simplify interaction with certifying authorities (CAs) on networks which use public-key infrastructure (PKI).
FreeIPA is an integrated Identity and Authentication solution for Linux/UNIX networked environments.
Ipsilon Federated Identity Provider
mod_nss is an SSL provider for Apache using the NSS crypto libraries
mod_revocator is an Apache module that retrieves and installs remote Certificate Revocate Lists (CRLs) into a running Apache web server without requiring a restart.