VIFF: Virtual Ideal Functionality Framework
===========================================

VIFF is a general framework for doing secure multi-party computations.
In a secure multi-party computation several parties jointly compute an
agreed function without leaking any information on their inputs. This
could be an election where the correct tally is computed *without*
revealing any information on the individual votes. In a protocol with
n players, the confidentiality of the inputs is ensured when up to n/2
of the players are corrupted.

VIFF is Free Software licensed under the GNU Lesser General Public
License (LGPL) version 3 or later. Please see the files COPYING and
COPYING.LIB for details. Please see doc/install.txt or
doc/html/install.html for installation instructions.


Features
--------

VIFF is still under development, but it is nevertheless quite usable
and offers the following features:

* secret sharing based on standard Shamir and pseudo-random secret
  sharing (PRSS).

* arithmetic with shares from Zp or GF(2^8): addition, multiplication,
  exclusive-or. Some support for actively secure multiplication.

* two comparison protocols which compare secret shared Zp inputs, with
  secret GF(2^8) or Zp output.

* reliable broadcast, even in the presence of active adversaries.

* computations with any number of players for which an honest majority
  can be found.

* optional support for encrypted TLS connections between the players.

All operations are automatically scheduled to run in parallel meaning
that an operation starts as soon as the operands are ready.

Should you encounter have problems with VIFF, then please start by
downloading the latest version on http://viff.dk/. If that does not
help, then ask for help on the VIFF mailing list at

  viff-devel@viff.dk

You can subscribe to the list at

  http://lists.viff.dk/listinfo.cgi/viff-devel-viff.dk

Please submit your bug reports to the VIFF Issue Tracker:

  http://tracker.viff.dk/


Example Applications
--------------------

The apps directory contains a number of example applications. They
require player configuration files to be generated in advance, use
apps/generate-config-files.py for that.

If you have installed the optional PyOpenSSL library, then run
apps/generate-certificates.py to generate the keys and certificates
for the players.

Finally, execute three players, starting with player 3, then player 2,
and finally player 1.