pluto - A Tor Hidden Service SMTP Relay using ORB. Tested with Mini Mailer and smtpdump.
The genkeys folder contains a small utility to create the keypair for ORB usage.
TLS certificates can be created with openssl.
$ openssl req -nodes -new -x509 -keyout key.pem -out cert.pem
An ORB is an Onion Reply Block, allowing you to hide your real
.onion email address, like Mixminion and the Nym Mixnet does
with SURBS.
You only need to give others your ORB block, so that others
can use it as reply block, to send you messages.
An ORB looks like this:
::
qr7cjQXe/7YsmbBhSLzOalGGJeCoGz9YzmDLwKWwp3fkBGMjGYYTLMGG0VPwTzBJ
sYtSQzYtZSXOCL5owEBhP9xsgnFA1dGjpKQnJYa9MMdLVe/sB2DFdrlbun2HoCvw
t64o+4rI90zRM5pz1QzkBWOKuDSFkH4btNn6I/fyt6kmGxUzFzb93DvDCnfNyQ==
::
You simply use minicrypt to encrypt your .onion email address
with the server's public key and then add the markers.
This is how a demo message looks like:
From: Mini Mailer <bounce.me@mini.mailer.msg>
To: orb@pluto.onion
::
qr7cjQXe/7YsmbBhSLzOalGGJeCoGz9YzmDLwKWwp3fkBGMjGYYTLMGG0VPwTzBJ
sYtSQzYtZSXOCL5owEBhP9xsgnFA1dGjpKQnJYa9MMdLVe/sB2DFdrlbun2HoCvw
t64o+4rI90zRM5pz1QzkBWOKuDSFkH4btNn6I/fyt6kmGxUzFzb93DvDCnfNyQ==
::
Hello World! :-)
This is a test with an ORB.
Regards
Stefan
And this is how it looks when the message arrived:
Received: from localhost (kubernetes.docker.internal. [127.0.0.1])
by iria (SMTPDump) with SMTP
for <pollux@fswlpxkp6xdrwrcu3dmby4lwv4z22bep32s3f3ffrua3x4bmvdyhg2ad.onion>;
Sat, 24 May 2025 23:54:50 +0200 (CEST)
From: orb@pluto.onion
To: pollux@fswlpxkp6xdrwrcu3dmby4lwv4z22bep32s3f3ffrua3x4bmvdyhg2ad.onion
Hello World! :-)
This is a test with an ORB.
Regards
Stefan
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