we need to implement our own PDF timestamping mechanism based on X509 certificate (including private key of course) and RFC 3161. I've googled and asked here on SO and proper solution would be to re-implement TSAClient class to do timestamping locally for us (without online TSA). However I didn't find any implementation of RFC 3161 except SecureBlackbox components. It should be possible with Bouncy Castle libraries but I don't know how.
Can you please point me to right direction?
It is possible to generate a RFC3161 timestamp token with Bouncycastle libraries.
First create a TimestampRequest. For your case it is only a wrapper for the digest algorithm and the digest value.
Then generate the token