1. Akamai Technology Limited, London, UK. E-mail: icarlson@akamai.com
2. Chalmers University of Technology, Gothenburg, Sweden. E-mail: aikmitr@chalmers.se
3. Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. E-mail: serge.vaudenay@epfl.ch