文档介绍：Privacy-Implications of Performance-Based
Peer Selection by Onion-Routers:
A Real-World Case Study using I2P
Michael Herrmann and Christian Grothoff
Technische Universit¨atM¨unchen, Munich, Germany
{herrmann,grothoff}***@
Abstract. I2P is one of the most widely used anonymizing Peer-to-Peer
networks on the today. Like Tor, it uses onion routing to build
tunnels between peers as the basis for providing munica-
tion channels. Unlike Tor, I2P integrates a range of anonymously hosted
services directly with the platform. This paper presents a new attack on
the I2P Peer-to-work, with the goal of determining the identity
of peers that are anonymously hosting HTTP services (Eepsite) in the
network.
Key design choices made by I2P developers, in particular performance-
based peer selection, enable a sophisticated adversary with modest re-
sources to break key security assumptions. Our attack first obtains an
estimate of the victim’s view of work. Then, the adversary selec-
tively targets a small number of peers used by the victim with a denial-
of-service attack while giving the victim the opportunity to replace those
peers with other peers that are controlled by the adversary. Finally, the
adversary performs some simple measurements to determine the identity
of the peer hosting the service.
This paper provides the necessary background on I2P, gives details on
the attack — including experimental data from measurements against
the actual work — and discusses possible solutions.
1 Introduction
Onion routing [13] is an established technique to provide sender- or receiver-
anonymity for low-work applications. Both Tor [2] and I2P [15] pro-
vide anonymity to their users via an work of onion routers run by
volunteers. However, there are significant differences in the details of how these
networks implement the basic technique. For many of the differences, the existing
related work does not provide a clear answer as to w