$Id: README,v 1.70.2.3 2003/12/23 23:08:14 nickm Exp $
======================================================================
This is Mixminion version 0.0.6.2.

CONTENTS:
        I.    Overview
        II.   What's new in this version
        III.  How to upgrade
        IV.   How to install
        V.    How to send messages
        VI.   How to run a server
        VII.  How to report bugs and suggestions
        VIII. Future interoperability
        IX.   How to contribute

I. OVERVIEW
===========

Mixminion is the standard implementation of the Type III anonymous remailer
protocol, which lets you send very anonymous email.  This best-of-breed
remailer uses conservative design approaches to provide security against most
known attacks.  We chose a simple, extensible design so that we can provide a
robust core system and then experiment with new research features such as
dummy policies, directory servers, and reputation systems.

You can find the latest information at http://mixminion.net/, or on the
mailing list, archived at http://archives.seul.org/mixminion/dev/.  Please
consider subscribing, especially if you're going to run a node.

This is a testing alpha release.  You will probably only want to use it if
you are technically inclined, curious, and interested in helping the
Mixminion development effort.

WARNING!  Do NOT use this release if you require strong anonymity.  It has
known deficiencies, including some that make it possible for an adversary
to trace your message through the system.

II. WHAT'S NEW IN THIS VERSION?
===============================

NEW IN VERSION 0.0.6.2:
   - Fixed a bug that prevented the client from ever deleting messages
     from its queue.

   - Have clients handle dropped connections to servers correctly, by 
     retrying only the packets that were not delivered.   

NEW IN VERSION 0.0.6.1:
   - Several documentation fixes.

   - Make the -H option work again when -P is not provided, and give a
     useful error when it is.

   - Make 'list-server -R' work properly.

   - Fix a bug that made it impossible to send replies messages with text
     from the command line.

   - Never try to clean client queues without holding the proper lock.

   - Prevent the server from crashing on an unresolvable hostname.

NEW IN VERSION 0.0.6:
   - Several documentation fixes.

   - Starting a server for the first time will no longer give a spurious
     message about an out-of-date installation.

   - We now accept as uniform several more recent versions of zlib.

   - 'mixminion server-start --quiet' is now even more quiet than before.

   - Inital initial debian packaging files and targes (Peter Palfrader)

NEW IN VERSION 0.0.6rc2:
   - Fixed a couple of bugs that would prevent Mixminion from running on
     Python 2.0 or Python 2.1.

   - Fixed a build problem with stand-alone Windows builds: the 'bsddb'
     module was not included, so we were defaulting to the slow and
     inefficient 'dumbdbm' module to store hash logs, SURB logs, and fragment
     indexes.

NEW IN VERSION 0.0.6rc1:
   - Windows support
       - The Mixminion command-line interface now works on MS Windows, at
         least for me.  It has been tested on Windows 2000, and should work
         on any platform running Windows 98 or later.  There are probably
         some lingering bugs, especially when running a server.

   - Improved security
       - SURB keys are now rotated periodically.

       - The client now _always_ shuffles packets before delivery, and sends
         them in a random order.

   - Improved robustness
       - Servers are now addressed by hostname rather than IP.  It is now
         feasible to run a Mixminion server with a dynamic IP address.
         Support for old-style routing will be deprecated in 0.0.7.
         (Servers use a DNS-farm abstraction to avoid blocking on slow
         DNS lookups.  MMTP connections are still authenticated, so attacks
         against DNS can at worst delay packets from arriving.)

       - The path generation logic has been largely rewritten to use the
         optimal routing method for each server-to-server pair.

       - The path generation code now chooses good paths for fragmented
         messages and messages with specific requirements on their exit
         nodes.

       - Client queues are generally less buggy.

       - Consistency enforcement between fragmentation and other modules.

       - Better spec compliance.

   - Improved performance
       - When flushing messages from the client queue, it is no longer
         necessary to load them all into RAM at once.

   - User interface tweaks
       - When running as a client, Mixminion now displays servers by nickname
         in addition to IP:port whenever possible.  Servers will gain this
         behavior in a later version, once they begin downloading
         directories.

       - The behavior of 'mixminion list-servers' has been changed: its
         default output is far terser and easier to parse than before, though
         output _even more_ verbose than previous can be selected.  Also,
         whereas the old implementation only listed servers by their
         lifetime, capabilities, and status, it is now possible to list
         arbitrary 'features' of the servers in the directory.

       - Error messages for timeouts are more reasonable; timeouts themselves
         should now work a little better than before.

       - A longstanding typo in the MMTP server's logging code has been
         resolved: running at DEBUG should be far terser and more reasonable
         than before.

       - Users can now send fragmented messages for reassembly by their
         recipients rather than exit servers.  (Client side reassembly is
         not yet implemented, however.)

       - Many error messages have been cleaned up, including a few related to
         SSL errors, Windows internals, corrupt databases, unsupported
         databases.

   - Build improvements
       - Use the preferred version of Python if one exists.

       - Add build target to output test vectors for crypto functionality.

       - Support the DESTDIR environment variable

       - Check SHA1 digest on downloaded OpenSSL 0.9.7c.

   - Other bugfixes too numerous to mention.

<See HISTORY file for changes in earlier versions.>

STILL NOT IN THIS VERSION:
   - There's a man page, but it's not included yet because I want it to
     work cross-platform.
   - IP-based restrictions don't work.
   - No support for distributed directories.
   - Other stuff too numerous to mention; see TODO.

III. HOW TO UPGRADE FROM MIXMINION 0.0.5
========================================

First, follow the installation instructions from section IV to install the
new version of the software.

If you aren't running a server, you are done.  (Compatibility note: SURB
keyrings used by version 0.0.5 are _not_ compatible with keyrings used by
0.0.6.X!)

If you're running a server, you may need to upgrade your configuration file.
Follow these steps:

    1. Your configuration file may be out of date.  You will need to add
        a 'Hostname' entry to the 'Incoming/MMTP' section of your
        configuration.  It _must_ contain a valid DNS name for your server.
        (You can use a static IP instead, if your server's IP will never
        change.)

        The 'IP' configuration entry is still required, too, in order to
        support older clients.

        (If you control your own DNS, you may want to consider creating a
        separate entry for your Mixminion server, so that you could move to a
        different host in the future as needed.)

    2. Start your server as usual ('mixminion server-start') and try sending
       some messages through it.  Check your configuration log for warnings.

IV. HOW TO INSTALL MIXMINION
============================

The quick version: For Unix-clones, Mac OS X, or Windows with Cygwin
---------------------------------------------------------------------
  <download and unpack http://www.mixminion.net/dist/Mixminion-0.0.6.2.tar.gz>

  % cd Mixminion-0.0.6.2
  % make download-openssl
  % make build-openssl
  % make
  % make test
 EITHER:
    % su
    Password:
    # make install
 OR:
    % make install PREFIX=~

The verbose version: For Unix-clones, Max OS X, or Windows with Cygwin
-----------------------------------------------------------------------

  1) You must have Python version 2.0 or later installed on your system.  The
     binary may be called "python", "python2", "python2.X", or something else.
     If you don't have Python >=v2.0, go install it.  You can find source and
     binary distributions at http://www.python.org/.

  2) If you have OpenSSL version 0.9.7beta3 or later, go to step 5.
     Otherwise, continue.

  3) Run "make download-openssl".

  4) Run "make build-openssl".  If this step fails, OpenSSL didn't build
     correctly on your system.  Go read contrib/openssl/INSTALL, and make
     OpenSSL build.

  5) Run "make".  If you don't get any error messages, go to step 6.

     If you have OpenSSL 0.9.7 installed, but the build script doesn't find
     it, you can force it to look in a particular location (say, "/home/ssl")
     with:
            make OPENSSL_PREFIX=/home/ssl
     This will make the scripts look for headers in $OPENSSL_PREFIX/include
     and libraries in $OPENSSL_PREFIX/lib.

     If the scripts *still* can't find OpenSSL 0.9.7, you can override the
     compile and link options directly, like this:
            make OPENSSL_CFLAGS='-I/home/ssl/include' \
                 OPENSSL_LDFLAGS='-L/home/ssl/libraries -lssl097 -lcrypto097'

     If your C compiler knows where to find OpenSSL on its own, but the
     build script doesn't trust it, you can disable searching like this:
            make SKIP_OPENSSL_SEARCH=y

     If you get any other errors, please report them to <nickm@freehaven.net>.

  6) Run "make test" to run Mixminion's unit tests.  If you get any errors,
     please report them to <nickm@freehaven.net>.

  7) Run "make install" to install Mixminion.  You may need to be root to
     execute this command.  By default, Mixminion will install itself relative
     to your python distribution.  If you want to install somewhere else (e.g.
     /home/miniond/), run "make install PREFIX=/home/miniond".

     A script called "mixminion" will be created in the 'bin' directory
     relative to your prefix, or in the same directory as the python
     executable if no prefix is provided.  To make sure that everything was
     installed correctly, you can run "mixminion unittests".

The very easy version: For Windows
----------------------------------

   First, make sure that you're running Win98 or later.

   Download 'Mixminion-0.0.6.2.win32.zip", and unpack it anywhere you like.
   It will create a directory named 'mixminion'.

   Use mixminion.exe from that directory as your command-line client.

   NOTE TO ALL WINDOWS USERS:  This is the first version of Mixminion to
   support native Win32 operations.  As such, you should consider it even
   more experimental than usual.  If you find any bugs, or any places where
   its behavior is stupid for a Windows environment, please let me know.
   (See section VII below for information on how to report bugs.)

The slightly harder version: For Windows with Python 2.3
--------------------------------------------------------

   First, make sure that you have the latest official release of Python 2.3
   installed.  As of 5 Dec 2003, this is 2.3.2.

   Download and run "Mixminion-0.0.6.2.win32-py2.3.exe".  It will unpack
   its files into your Python directory.

   The script to invoke Mixminion will be stored in the 'Scripts'
   subdirectory of your Python directory.  Whenever the instructions below
   tell you to run 'mixminion', run "python Scripts\mixminion.py' instead,
   from the python directory.  (Future releases may include a batch file
   to make this easier, especially if somebody else contributes one.)

   Be sure to read the "NOTE TO ALL WINDOWS USERS" above.

The verbose version: How to build on Windows
--------------------------------------------

   (I have only tried this with Visual Studio 6 and Python 2.3.  Let me know
   if you succeed with any other compilers.  Also, let me know if these
   instructions don't work.)

   First, install Python version 2.0 or later, either from the official
   binary or by building it yourself.  When you build Mixminion, you will
   need to use the same compiler as was used to build Python: the standard
   distribution uses Visual Studio 6.

   Second, download an unpack the Mixminion source distribution.

   Third, get a compiled copy of OpenSSL version 0.9.7 or later (as of 5 Dec
   2003, the latest stable version is 0.9.7c).  You can either compile it
   yourself, or use a set of precompiled binaries (such as are available from
   XXXX).  Place the compiled libraries under the "contrib" directory in the
   Mixminion source directory, so that the include files are in
   "contrib\OpenSSL\include" and the libraries are in
   "contrib\OpenSSL\lib\VC".

   Now you are ready to build Mixminion!  Make sure that python.exe is on
   your path, then run:

         python setup.py build
         python setup.py run --subcommand=unittests

   If all the unit tests pass, you can either install the software locally
   and use it as described in 'the slightly harder version' above:

         python setup.py install

   Or you can make a windows installer for users with Python:

         python setup.py bdist_wininst

   Or, if you have the py2exe package installed, you can make a standalone
   binary that people can run without installing Python:

         python setup.py py2exe

   Finally, be sure to read the "NOTE TO ALL WINDOWS USERS" above.

V. HOW TO SEND MESSAGES VIA MIXMINION
=====================================

Just run one of the following command lines:

        mixminion send -t <email address> -i <filename to send>
    OR  mixminion send -t <email address>            (to read from stdin)
    OR  mixminion send -t <email address> -i -       (also reads from stdin)

Mixminion will then take the following steps:

     A) Download and validate the latest server directory.
        (But only if you haven't done so since midnight GMT.)
     B) Select a path that ends at a server with SMTP support.
        (Currently, this defaults to 4 hops.)
     C) Read your message.
     D) Construct a Type III Mix packet containing your message.
        (For more information, see the links at http://www.mixminion.net/)
     E) Send the message to the first server in your path.

To specify headers, use any of the following options:

      --subject=<subject line to use>
      --in-reply-to=<in-reply-to line to use>
      --references=<references line to use>
      --from=<from address to use>

      All are used verbatim, except for 'from', which the exit server wraps
      in an envelope to indicate that the address is anonymous.  For example,
      if you specify --from="Tristero", your recipient will get an email that
      says something like "From: "[Anon] Tristero" <nobody@remailer>".

To see a list of currently known servers, type:

      mixminion list-servers

      You can change the format and contents of this listing.  For more
      information, run 'mixminion list-servers --help'.

To force a reload of the server directory, type:

      mixminion send -t <address> [-i <file>] -D yes

To send a message _without_ reloading the directory, type:

      mixminion send -t <address> [-i <file>] -D no

To reload the directory without sending a message, type:

        mixminion send -D yes
     OR mixminion update-servers

To see whether a server is running, type:

      mixminion ping <servername>

      (WARNING: This command is potentially dangerous, for a number of subtle
      and not-so-subtle reasons.  It will go away before Mixminion 1.0.)

To force a path of a given length, type:

      mixminion send -t <address> [-i <file>] -H <number of hops>

      You can change the default number of hops by editing ~/.mixminionrc

To specify a path manually, type:

      mixminion send -t <address> [-i <file>] -P <path>

      The argument <path> must be a comma separated list of either:
          (a) Server nicknames as given by 'list-servers'
          (b) Paths to files containing server descriptors [more info below]

      For example, to send a message through the servers Foo, Bar, Baz, and
      Quux, you would type "-P Foo,Bar,Baz,Quux."

      To specify a randomly chosen server, you can include a question mark,
      like this:
             -P 'Foo,?,Bar,?'     [Foo, a random server, Bar, and another
                                   random server]

      You can specify a sequence of N random servers like this:
             -P 'Foo,*3,Bar'      [Foo, three random servers, then Bar.]

      You can specify a random-length sequence of *about* N servers like
      this:
             -P 'Foo,~3,Bar'      [Foo, about three random servers, then Bar.]

      {ADVANCED} By default, the swap point will be halfway through
      the path (rounding up). To specify a swap point explicitly, use
      a colon in your path, as in:
             -P 'Foo,Bar:Baz,Quux'    [Swap headers at server Bar]
             --swap-at=<n>            [Swap headers at the n'th server]
      If you don't know what a swap point is, don't worry. :)

If you want to use the same path by default for all of your messages,
edit the  ~/.mixminionrc and change the ForwardPath line:

      # By default, use the same servers for entry and exit each time,
      # with about three randomly chosen servers in the middle.
      ForwardPath: FavoriteEntry,~3,FavoriteExit

To send a dummy message, specify "drop" instead of an email address, as in:

      mixminion send -t drop
      mixminion send -t drop -P '*4,Foo'
      mixminion send -t drop -H 8

To queue a message for later transmission, run "mixminion queue" instead of
"mixminion send":

      mixminion queue -t <address> -i <file> -P <path>

      To see all the packets waiting in the queue:

      mixminion inspect-queue

      To attempt to deliver all messages waiting in the queue:

      mixminion flush

      To attempt to deliver no more than 16 messages:

      mixminion flush -n 16

      To remove messages that have been waiting in the queue for more than
      seven days:

      mixminion clean-queue -d 7

      (QUEUE NOTE: By default, when "mixminion send" fails to deliver a
      message, it leaves that message in the queue to be reattempted later.
      To suppress this behavior, use the "--no-queue" option:
            mixminion send --no-queue -t <address> -i <file> -P <path>
      Also, as a final side note, "mixminion send --queue" is a synonym for
      "mixminion queue".)

To decode a message you have received, type:

      mixminion decode -i <input-file> -o <output-file>.

      Or, to send output to stdout:

      mixminion decode -i <input-file>

      (When you receive a message with non-printing characters via email, it
      will be encoded in base64 before delivery.  When you receive a reply,
      its contents will be encrypted.  The "mixminion decode" command
      extracts the original text from either kind of message as best it can.)

To generate a reply block, type:

      mixminion generate-surb -t <your-address>

      To send the reply block to a file, instead of to stdout:

      mixminion generate-surb -t <your-address> -o <filename>

      If you specify a "SURBAddress" field in ~/.mixminionrc, you may
      omit the target address:

      mixminion generate-surb

      Also, you can control path selection in the same way as with
      sending messages:

      mixminion generate-surb -H 3         (a 3-hop path)
      mixminion generate-surb -P '*3,Foo'  (a 4-hop path ending with foo)
      mixminion generate-surb -P 'Bar,*3'  (a 4-hop path starting with bar)

      You can use the '-n' option to generate many reply blocks at once:

      mixminion generate-surb -n 100      (generate 100 reply blocks)

      To save space, you can specify binary (as opposed to text) encoding
      for your reply blocks:

      mixminion generate-surb -b -o <filename>

      By default, the client will choose servers to make sure that your
      reply blocks will still function for 7 days.  To choose a different
      lifetime:
         mixminion generate-surb --lifetime=1           (1 day)
      Note that if you choose an overlong lifetime, there may not be enough
      servers whose keys will be valid for the entire period.

      If you maintain multiple pseudonymous identities, to avoid a
      SURB-swapping attack, you should use the --identity option so that
      you can later see which messages were to sent to which SURB identity.
         mixminion generate-surb --identity=alice -o alices_surb
         mixminion generate-surb --identity=bob   -o bobs_surb

Once you have a reply block for a user, you can send reply messages by
typing:

      mixminion send -R <reply-block-filename> -i <input-filename>

      The other options to 'send' and 'pool' still apply; the reply block
      takes the place of the destination address:
         mixminion send -R <reply-block>           (Read from stdin)
         mixminion send -R <reply-block> -D yes    (Reload directory)
         mixminion send -R <reply-block> -H 4      (Use 4 hops before reply.)
         mixminion send -R <reply-block> -P 'Z,*3' (Start with server "Z".)
         mixminion pool -R <reply-block>           (Pool the message.)

      IMPORTANT: Mixminion reply blocks can only be used once!  (Thus,
      SURB="Single Use Reply Block".)  The program will remember which
      reply blocks it has used in the past, but if you give a single reply
      block to 2 users, it will only work for one of them, once.

      As a convenience, if you have a file containing many reply blocks,
      you can use it with '-R': the client will choose the first reply
      block from the file which has not expired, and which you have not
      yet used.

      To inspect the reply blocks in a file, you can run:
         mixminion inspect-surbs <filename>

If you need to use a proxy server to use the web you can specify it using the
http_proxy environment variable:

      export http_proxy=http://proxy:3128/
      mixminion send -D yes


VI. HOW TO RUN YOUR OWN MIXMINION SERVER
========================================

1) Create a copy of the "etc/mixminiond.conf" file from the
   mixminion distribution and place it where you like.  Mixminion will
   automatically look in ~/.mixminiond.conf, ~/etc/mixminiond.conf, and
   /etc/mixminiond.conf.  However, you can store it anywhere.

2) Edit mixminiond.conf to reflect your own system settings.

3) Run your server for the first time:

        "mixminion server-start -f <path to mixminiond.conf>"

    (The -f flag and path are only necessary if you placed the
    configuration file somewhere other than ~/.mixminiond.conf,
    ~/etc/mixminiond.conf, or /etc/mixminiond.conf.)

5) To try out your server, clients will need a copy of your server
   descriptor, whose location is stored $SERVER_HOME/current-desc.

   For example, if your mixminiond.conf contains the following line:

           Homedir: /home/mixminion/spool

   Then if you read the contents of /home/mixminion/spool/current-desc,
   you will find a filename like:

           "/home/mixminion/spool/keys/key_0001/ServerDesc".

   This file is your current server descriptor.

   Mixminion supports a global directory of server descriptors.  Until you
   are listed in that directory, clients can import your ServerDesc file
   (if they have a copy) by hand by running:

           mixminion import-server <filename>

   They can also use your ServerDesc without importing it by using the
   filename as a part of their path:

           mixminion send -t <address> -P '<filename>,?,?'

6) When you're ready to advertise your server, edit 'mixminiond.conf' and set
   the 'Publish' option to 'yes'.  When you restart your server, it will
   advertise itself to the central directory.

   The first time you do this, your server will not be inserted automatically;
   the directory server holds your server's information separately until I
   confirm it (to prevent pseudospoofing).  Once your server is listed, future
   updates will be get into the directory automatically.

   WARNING: We don't have statistics yet, so the system isn't robust in the
   presence of unreliable servers in the directory.  Please don't publish a
   server if you don't think you can keep it up for a good while.

   {This step will be more automated in later versions.}

To shut down a server:
    mixminion server-stop [-f configfile]

To make a server reload its configuration:
    mixminion server-reload [-f configfile]

    (Right now, this just closes and re-opens the log files.)

Your server can be configured to keep track of the number of packets it
receives and other interesting statistics.  Ordinarily, it aggregates these
totals and flushes a report to disk at a configurable interval.  If you want
to see statistics in the _current_ interval, run:

    mixminion server-stats [-f configfile]


VII. HOW TO REPORT BUGS AND SUGGEST NEW FEATURES
================================================

To report bugs, please use the Bugzilla pages at http://bugs.noreply.org.

For other correspondence, please email <nickm@freehaven.net>.

For help in debugging, please try to send a copy of:
        * What command you were running
        * The complete error you got, including stack trace (if any)

If your error occurred on a running server, please make a copy of your
log--it might be helpful.

VIII. FUTURE INTEROPERABILITY
=============================

Mixminion is not yet feature complete.  As the software moves closer to
official release, backwards-incompatible changes *WILL* be introduced.
Future versions of Mixminion, including future versions in the 0.x track, may
reject messages from older versions as additional security features are
added.

Furthermore, the present preview versions include necessary diagnostic
features that potentially compromise anonymity and would be inappropriate in
a production system; these features will be removed or disabled by 1.0.

IX. HOW TO CONTRIBUTE
=====================

Send patches to <nickm@freehaven.net>.  If you can, please submit unified
diffs against the latest version of the code in CVS.

Make sure to run 'make test' before you send in any patches, so you can see
whether your patch broke existing code.  (It's okay if you're not sure how to
fix the test, but please let me know when you send your patch.)

------------------
(for emacs)
  Local Variables:
  mode:text
  indent-tabs-mode:nil
  fill-column:77
  End:
