EJBCA

Developed since 2001, EJBCA is one of the most complete PKI management open source solutions there is. It is currently driven and actively maintained by Swedish company PrimeKey.

Like other PKI solutions, EJBCA can handle all aspects of standard X509 certification, from certificate issuing, CRL revocations to certification chains, and it is one of the only products to implement a large number of the standards linked to specification X509 (OCSP responder, CMS, and so forth). Its management of custom hardware such as HSMs is quite accurate. It also offers a complete admin interface with rights restrictions and a client portal.
For several months now, EJBCA has also offered support for innovative protocols for iPhones (SCEP standard) and partial support for emerging technologies (CMP, XKMS, etc.). EJBCA is covered by the LGPL and has only one edition. Commercial support can be subscribed to with the vendor, PrimeKey.
From a technical perspective, EJBCA is entirely written in Java and is powered by a JEE application server, which could be either JBoss or GlassFish. Compatible with a vast array of proprietary and open source database engines, it is one of the rare products that fully complies with Java Beans specifications.