[tor-talk] How to use flashproxy-reg-url

[David Fifield]

The latest pluggable transports bundles and flashproxy source releases
contain a new rendezvous program called flashproxy-reg-url. Like
flashproxy-reg-email, which is the default, it provides a covert way to
send your address so that you can receive a connection from a flash
proxy. Unlike flashproxy-reg-email, it is still experimental and doesn't
work out of the box: you need to find your own URL retrieval service.
This post is about how to make it work.

When you run the flashproxy-reg-url program and give it your external IP
address and the port that flashproxy-client is listening on, it will
print out a URL. The URL encodes an encrypted representation of your
address and port. When this URL is retrieved--by anyone or anything--the
facilitator decrypts the message and registers your address, and you
should get a flash proxy connection right away.

For example, if you run
	./flashproxy-reg-url 192.0.2.1:9000
the program will print out a long URL like
	https://tor-facilitator.bamsoftware.com/reg/0labtDob545HeKpLZ8LqGeOi-OK7HXoQvfQzj0P2pjh1NrCKNDaPe91zo...
Now is where you must get creative. Of course you can paste the URL into
a browser yourself, but we're assuming that a censor will block direct
access to this web server. You can email the URL to someone you trust
who is not being censored. There are also a lot of services on the web
that will take any URL you give them and try to retrieve it--any of
those that are not blocked by the firewall will work.

The censorship-resistance of this approach comes from the idea that
there are so many ways to cause a URL to be retrieved that they cannot
all be blocked. If the service you use uses encryption (for example
HTTPS), then the censor cannot filter on the distinctive form of the
URLs either.

How do I find out my IP address and port number? By default the port
number is 9000, but you might have changed it with the instructions at
https://trac.torproject.org/projects/tor/wiki/FlashProxyHowto. The IP
address can be IPv4 or IPv6. You can find out your address using a
service like https://www.whatismyip.com/.

Here is the program man page:
https://gitweb.torproject.org/flashproxy.git/blob/HEAD:/doc/flashproxy-reg-url.1.txt
Here is the ticket about the creation of the program:
https://trac.torproject.org/projects/tor/ticket/7559

David Fifield