Hi Beck. Unfortunately at this point you know far more about descriptor crypto than me so I won't be much help. A quick search in apt for 'pkcs' only came up with one python result, PyKCS11 (http://www.bit4id.org/trac/pykcs11), which looks to be mostly related to smartcards. Hopefully Karsten will have some suggestions.
PS. Are you guys getting email updates from ticket #5810? I'm doubting that you two are not actually CCed since no one is replying...
Yes. Both Karsten and I are subscribed to tor-bugs@ so we see all trac updates.
PSS. Do we need to keep Ravi in this conversation?
Nope, everyone on this thread is on tor-dev@ already. If you aren't on this list yourself then I'd suggest it. :)
PSSS. Should I wrap up my email to 78 words per line?
Really doesn't matter. Some people care strongly about it, others don't. I'm in the later camp but do it anyway since I think it looks a little nicer and gmail defaults to 80-character wrap when you chose plaintext.
Cheers! -Damian