> What encryption algorithms does Tor use?

See the following sections of the [Tor Protocol Specification][1]:

 - 0.2 Security parameters
 - 0.3 Ciphers

> Isn't RSA 1024 considered weak?

1024 hasn't been broken (yet... ), and you'd find moving to anything bigger makes things generally slower. (Together with the fact that you'd have to make the length of .onion addresses longer, and the hassle therein.)

There's a useful discussion in [this][2] old thread.

With regards to rolling your own more secure onion service, have a look at [this][3] thread.


  [1]: https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt
  [2]: https://tor.stackexchange.com/questions/760/what-is-the-reasoning-behind-keeping-hidden-service-onion-rsa-keys-at-1024-lengt?rq=1
  [3]: https://tor.stackexchange.com/questions/3371/hidden-onion-service-with-2048-bit-or-4096-bit-rsa-private-key-how-to-host