The right to communicate with your friends and family in private,
-without anyone snooping, is a right every citicen have in a liberal
-democracy. But this right is under serious attack these days.
-
-
A while back it occurred to me that one way to make the dragnet
-surveillance conducted by NSA, GCHQ, FRA and others (and confirmed by
-the whisleblower Snowden) more expensive for Internet email,
-is to deliver all email using SMTP via Tor. Such SMTP option would be
-a nice addition to the FreedomBox project if we could send email
-between FreedomBox machines without leaking metadata about the emails
-to the people peeking on the wire. I
-proposed
-this on the FreedomBox project mailing list in October and got a
-lot of useful feedback and suggestions. It also became obvious to me
-that this was not a novel idea, as the same idea was tested and
-documented by Johannes Berg as early as 2006, and both
-the
-Mailpile and the Cables systems
-propose a similar method / protocol to pass emails between users.
-
-
To implement such system one need to set up a Tor hidden service
-providing the SMTP protocol on port 25, and use email addresses
-looking like username@hidden-service-name.onion. With such addresses
-the connections to port 25 on hidden-service-name.onion using Tor will
-go to the correct SMTP server. To do this, one need to configure the
-Tor daemon to provide the hidden service and the mail server to accept
-emails for this .onion domain. To learn more about Exim configuration
-in Debian and test the design provided by Johannes Berg in his FAQ, I
-set out yesterday to create a Debian package for making it trivial to
-set up such SMTP over Tor service based on Debian. Getting it to work
-were fairly easy, and
-the
-source code for the Debian package is available from github. I
-plan to move it into Debian if further testing prove this to be a
-useful approach.
-
-
If you want to test this, set up a blank Debian machine without any
-mail system installed (or run apt-get purge exim4-config to
-get rid of exim4). Install tor, clone the git repository mentioned
-above, build the deb and install it on the machine. Next, run
-/usr/lib/exim4-smtorp/setup-exim-hidden-service and follow
-the instructions to get the service up and running. Restart tor and
-exim when it is done, and test mail delivery using swaks like
-this:
-
-
-torsocks swaks --server dutlqrrmjhtfa3vp.onion \
- --to fbx@dutlqrrmjhtfa3vp.onion
-
-
-
This will test the SMTP delivery using tor. Replace the email
-address with your own address to test your server. :)
-
-
The setup procedure is still to complex, and I hope it can be made
-easier and more automatic. Especially the tor setup need more work.
-Also, the package include a tor-smtp tool written in C, but its task
-should probably be rewritten in some script language to make the deb
-architecture independent. It would probably also make the code easier
-to review. The tor-smtp tool currently need to listen on a socket for
-exim to talk to it and is started using xinetd. It would be better if
-no daemon and no socket is needed. I suspect it is possible to get
-exim to run a command line tool for delivery instead of talking to a
-socket, and hope to figure out how in a future version of this
-system.
-
-
Until I wipe my test machine, I can be reached using the
-fbx@dutlqrrmjhtfa3vp.onion mail address, deliverable over
-SMTorP. :)
-
