Kostas Chatzikokolakis

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Location Guard

Location Guard is a browser extension that allows to protect your location while using location-aware websites, by adding controlled noise to it. It supports Chrome / Chromium, Mozilla Firefox / Firefox for Android and Opera. 50k+ users.

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Install: Chrome / Firefox / Opera

In the press:

libqif - A Quantitative Information Flow C++ Toolkit Library

The goal of libqif is to provide an efficient C++ toolkit implementing a variety of techniques and algorithms from the area of quantitative information flow and differential privacy. We plan to implement all techniques produced by Comète in recent years, as well as several ones produced outside the group, giving the ability to privacy researchers to reproduce our results and compare different techniques in a uniform and efficient framework.

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Co-founded in 2003 the greek social networking site www.zoo.gr (greek only). Today it's one of the most popular greek web sites.

A tool to check demonic bisimulation

The tool decides demonic bisimulation for an extension of probabilistic CCS with syntactic schedulers. The input is two finite CCS processes. The tool converts them to a probabilistic automaton, and then implements an algorithm to decide bisimulation for such automata. More information can be found in the FOSSACS'09 paper.



LCI is an interpreter for the lambda calculus. It supports many advanced features like recursion, user-defined operators and multiple evaluation strategies, all based on the pure calculus.

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Small tools developed for my thesis

Requirements: These scripts require Perl to run and have been tested in Linux. The GUI of the corners tool also requires the Perl/TK library. Finally some parts of the model generator tool require PRISM and gnuplot to be installed.