Following the 'release it early and often' mantra I've put up pg-cert 0.1.0. It is extremely primitive but it allows you to save and restore certs in OpenSSL format(*) and retrieve most of the "basic" information that all certs are required to have:
1. Serial Number (BIGNUM)
2. Not-Before Date (TIMESTAMP)
3. Not-After Date (TIMESTAMP)
4. Issuer (TEXT for now)
5. Subject (TEXT for now).
The two missing values are the basic constraint (can the cert be used to sign other certs - a boolean flag) and the public key associated with the cert.
Besides being minimally useful (in the good sense) this gives everyone an idea about how the OpenSSL and PostgreSQL code can play together.
BTW I know that OpenSSL allows you to specify your own memory management functions and I've set it to use palloc() and pfree() in the past. I don't know what the production system does and am obviously not going to screw up anything.
Bear