Add option to serve files via Tor hidden service

[philippgille]

Tor hidden services (v3) have the advantage of being accessible from the internet without having to set up any port forwarding from the router (that's using NAT). Additionally the traffic is encrypted by default.

It should be possible to launch a temporary hidden service with a single simple serve command.

Libraries:

• For the Tor service itself: https://github.com/ipsn/go-libtor
  • Mentions it can be used with bine
  • Maybe as an alternative: https://github.com/cretz/tor-static
• For creating a hidden service: https://github.com/cretz/bine
  • Mentions it can be used with tor-static

With those libraries it should be possible to include Tor in the single serve binary, without requiring the user to install anything.

Other info:

• Also check out https://github.com/lightningnetwork/lnd, which includes the option to create a Tor hidden service and it's a single binary as well
• Read https://2019.www.torproject.org/docs/tor-onion-service.html.en
• Regarding HTTPS: https://blog.torproject.org/facebook-hidden-services-and-https-certs
• https://stem.torproject.org/tutorials/over_the_river.html
  • Mentions https://tor2web.org/ to test if a hidden service works without having to use Tor on the client side
• For setting up client authorization: https://2019.www.torproject.org/docs/tor-manual-dev.html.en#_client_authorization
  • But maybe our current HTTP Basic Authorization is enough?
• Also check out https://github.com/micahflee/onionshare