From: rjc@gnu.ai.mit.edu (Ray)
Date: Tue, 15 Mar 94 17:18:18 PST
To: cypherpunks@toad.com
Subject: my improved anonymous remailer
Message-ID: <9403160118.AA25354@geech.gnu.ai.mit.edu>
MIME-Version: 1.0
Content-Type: text/plain



  Cypherpunks,

    Seeing as how everyone else is announcing their anonymous remailers,
I may as well announce mine which is nearing completion. The remailer
is written in Knuth's WEB using Perl so there is nice documentation.
The remailer includes among other things, virtual addresses (handles),
padding/packetizing messages (splitting them up and sending pieces through
multiple remailer chains), chaining, mixing, a key-server, a list of
remailers server, a socket-server to bypass the sendmail queue and
get immediate error return, a stealth mode (delivery via direct SMTP or
socket instead of through the local sendmail), secure remailer network
(remailers sign and encrypt chained messages between each other), 
fake remailer traffic, and other small features. The virtual handles are 
fairly secure. They can be stored in the database as either plaintext real 
email addresses, virtual addresses located elsewhere on the remailer network, 
or SAEE cypherpunk remailer blocks (self-addressed encrypted envelope)

   The following text is taken from the WEB document and contains some
addition information. Send any comments you have to me, 
rjc@gnu.ai.mit.edu

-Ray
p.s. I expect that it will be ready for beta release in about two weeks.
At that point, I would need some beta testers to set up a remailer network
to make sure the socket-based and e-mail based networking works
(especially the packetizing)

p.p.s. e-mail commands are of the same form as the extropian's mailing
list, backwards compatibility with the cypherpunks pasting token is not
supported. Why? All headers in the message are ignored (and in socket-mode,
there is no header anyway) and the prefered mode of operation is to encrypt 
the body and the commands so no outside eyes can see the remail request
destination nor the message subject.

------------------------------CUT HERE---------------------------------------
\documentstyle{article}
\title{Remailer 2.0 \\ An Improved Anonymous Remailer}
\author{Ray Cromwell \\ rjc@@gnu.ai.mit.edu}
\date{March 1, 1994}

%$Id: remailer.w,v 0.2 94/03/01 03:22:27 rcromw1 Exp $

\newcommand{\rem}{{\tt Remailer 2.0\ }}
\begin{document}
\maketitle
\tableofcontents

\section{Introduction}

  The following text describes an improved anonymous remailer based on
suggestions Tim May made on the cypherpunks\footnote{Send subscription
requests to cypherpunks-request@@toad.com} mailing list a few weeks ago.
I was stuck in the middle of school work and the {\em Extropians List
Software} when Tim made the anouncement, but I had plenty of ideas on
how to implement and improve remailers. So here at last is the result of
my hacking.

\begin{center}
{\Large Remailer Improvement Principles}
\begin{itemize}
\item Secure Virtual Addresses
\item Chaining
\item Mix Delays
\item Fake Remailer Traffic
\item Padding/Packetizing Messages
\item Builtin Remailer List Generation
\item Builtin Public Key Server
\item Socket Operation
\item Stealth on Multiuser Systems
\item Open Design
\item Simple ``.forward'' Mode Operation
\end{itemize}
\end{center}

[...]
\subsubsection{Socket Mode}

  Socket mode provides a more secure form of operation by bypassing the
standard sendmail delivery mechanism allowing a message to be
piped directly to the remailer. In addition, the socket mode remailer
functions as an information server allowing clients to request
a publically networked list of public keys and up-to-date list of
\rem servers. The port number can be anything but I'm suggesting we all 
agree to use port 2258.

  Upon connection to the remailer port, a greeting message will be sent to you
of the following form. On the first line is a general greeting message
which can be any string. On the next line is status information separated
by ``/''. The status information in order is: \verb|remailer_name|,
version, administrator e-mail address, and finally a list of flags.
The flags are single character upper case letters specifying
the following options. {\bf P} to specify that the machine is 
privately owned and single-user, {\bf M} for mixing enabled, {\bf C} for 
chaining, {\bf K} if the keyserver is turned on, {\bf E} if this remailer
only accepts encrypted messages, and {\bf S} if stealth mode is on.


\begin{center}
\begin{verbatim}
Example:
telnet remailer.nsa.gov 2258
Connected to remailer.nsa.gov
Escape character is '^]'
Greetings, Welcome to Billy Bob Jake's Super Deluxe Remailer!
bob_remailer/Version 1.1/bob@@remailer.nsa.gov/PMCKESF
\end{verbatim}
\end{center}

  While connected, entering {\bf list} for example, would get you a list of 
remailers, or {\bf keys} for an index of keys. You can also remail at this 
point and even get an error status.

[...]

\subsection{Reading and Writing the Remailer List}
   The remailer list is a simple text file which consists of a list
of lines each containing a \verb|remailer_name|, ':', the e-mail address
of the remailer, the flags for that remailer, and a timestamp
recording the last time a response was received from this remailer. Each
field is separated by a comma. `\#' Comments and null lines are allowed.
A visible comment can be attached to a remailer by using the form
``\verb|remailer_name|\%comment string'' Additional comments to the
same \verb|remailer_name| are concatenated.

[...]

\begin{verbatim}
Example:
ann's remailer: ann_remailer@@host.domain,PKCMS,77676734
ann's remailer% My remailer is special because my machine has
ann's remailer% TEMPEST shielding around it. It can also self destruct
ann's remailer% in the event of an NSA raid.
\end{verbatim}

\subsection{Database Functions}

  \rem uses a dbm database to record information neccessary to implement
``Virtual Addresses'' These are penet\footnote{`penet' refers to the anonymous
posting service running at \verb|anon.penet.fi|. Send mail to 
\verb|help@@anon.penet.fi| for information.} style handles used by the 
anonymous remailer network to allow easy addressibility to anonymous
recipients without the complication of anonymous encrypted return
address blocks.

  Each record in the virtual database is keyed by the handle in the virtual 
address itself. A record contains 3 fields right now. The first is the
storage method, the second is the user address connected with the handle.
The third is a timestamp revealing the last time this address was
used. Later, a fourth record might be added for electronic postage.

[...]

\subsubsection{Virtual Addresses, A Side Note}

   Virtual Addresses consist of a {\bf user handle} and an optional 
{\bf remailer name} separated by `{\bf \#}' I used `\#' because I wanted
to differentiate virtual addresses from internet style addresses.
An example of a virtual address is ``darkmodem\#deepanon'' which
means that the message should be sent to the user connected with the
handle ``darkmodem'' through the remailer named ``deepanon'' You can
chain your own remailers by simply adding multiple remailer names to the
virtual address. For example, ``user\#remailer1\#remailer2\#remailer3''
which will send the message first through remailer1, then remailer2,
then remailer 3, and finally to whoever happens to be connected with
``user''. A special remailer name ``*'' is provided. Each instance of
``*'' in a remailer chain will be replaced by a random remailer.
For example, ``darkmodem\#*#*#deepanon'' will first chain the message
through two random remailers and then finally to deepanon. The random
remailers chosen are not guaranteed to be unique.

[...]	
\section{Change History}
\begin{verbatim}
$Log:	remailer.w,v $
Revision 0.2  94/03/01  03:22:27  rcromw1
prerelease

\end{verbatim}
\section{Identifier Index}
@u
\end{document}


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-- Ray Cromwell        |    Engineering is the implementation of science;   --
-- rjc@gnu.ai.mit.edu  |       politics is the implementation of faith.     --