As mentioned before I wrote some PHP class to allow people writing PHP applications to (ab)use the authentication method UGent and DICT offer easily.
This is the documentation of it, rendered using PhpDocumenter. The code of the class can be found inside the docs (can't give a link here, b2evo bug :-/), a working demo is here.
The code uses 2 mechanisms to decrypt the RSA encrypted key we get from the authentication server: it tries to use PHP's internal openssl_* set of functions, if support for them is compiled in the PHP interpreter. Otherwise it falls back to shell_exec to call OpenSSL in a shell, which gives a lot of overhead, unfortunately.
Unlike the provided samples, I'm not using temporary files anywhere.
Just installed Evince. It got some more features than Gpdf already, let's hope it continues to grow :-)