Title: INTRODUCTION

Introduction

GNUnet is a pure P2P system that is all users behave the same way with respect to use and supply of services and functionality. In particular, there is no (central) directory service as in Onion Routing or the Blender in Crowds [Deliverable 13.1, Section 7.2]. Contents available within the network are redundantly stored in a distributed manner on several clients. In general, however, none of the clients entirely stores entire file content, but a share of a file, for instance.  

The most significant difference between GNUnet and similar organized systems like Crowds or Onion Routing is the objective. GNUnet intends to provide anonymity for requests, which target resources within the network rather than public web servers, for instance, which are outside the GNUnet. Thus, resources need to be explicitly propagated to the network. This difference is important for the preservation of anonymity, since a lot of known attacks, which affect other anonymity services, are based on linkability analysis of data which appears right on the border of such systems. That is, the adversary grasps such anonymity services as black boxes and watches their inputs and outputs. Connections can be worked out, for instance, by comparing the amount of data between users and anonymity service with the amount between anonymity service and a dedicated web server.