28,499 research outputs found
Maintaining unlinkability in group based P2P environments
In the wake of the success of Peer-to-Peer (P2P) networking, security has arisen as one of its main concerns, becoming a key issue when evaluating a P2P system. Unfortunately, some systems' design focus targeted issues such as scalabil-ity or overall performance, but not security. As a result, security mechanisms must be provided at a later stage, after the system has already been designed and partially (or even fully) implemented, which may prove a cumbersome proposition. This work exposes how a security layer was provided under such circumstances for a specic Java based P2P framework: JXTA-Overlay.Arran de l'èxit de (P2P) peer-to-peer, la seguretat ha sorgit com una de les seves principals preocupacions, esdevenint una qüestió clau en l'avaluació d'un sistema P2P. Malauradament, alguns sistemes de disseny apunten focus de problemes com l'escalabilitat o l'acompliment general, però no de seguretat. Com a resultat d'això, els mecanismes de seguretat s¿han de proporcionar en una etapa posterior, després que el sistema ja ha estat dissenyat i parcialment (o fins i tot totalment) implementat, la qual cosa pot ser una proposició incòmode. Aquest article exposa com es va proveir una capa de seguretat sota aquestes circumstàncies per un Java específic basat en un marc P2P: JXTA-superposició.A raíz del éxito de (P2P) peer-to-peer, la seguridad ha surgido como una de sus principales preocupaciones, convirtiéndose en una cuestión clave en la evaluación de un sistema P2P. Desgraciadamente, algunos sistemas de diseño apuntan un foco de problemas como la escalabilidad o el desempeño general, pero no de seguridad. Como resultado de ello, los mecanismos de seguridad se proporcionarán en una etapa posterior, después de que el sistema ya ha sido diseñado y parcialmente (o incluso totalmente) implementado, lo que puede ser una proposición incómodo. Este artículo expone cómo se proveyó una capa de seguridad bajo estas circunstancias por un Java específico basado en un marco P2P: JXTA-superposición
One Bad Apple Spoils the Bunch: Exploiting P2P Applications to Trace and Profile Tor Users
Tor is a popular low-latency anonymity network. However, Tor does not protect
against the exploitation of an insecure application to reveal the IP address
of, or trace, a TCP stream. In addition, because of the linkability of Tor
streams sent together over a single circuit, tracing one stream sent over a
circuit traces them all. Surprisingly, it is unknown whether this linkability
allows in practice to trace a significant number of streams originating from
secure (i.e., proxied) applications. In this paper, we show that linkability
allows us to trace 193% of additional streams, including 27% of HTTP streams
possibly originating from "secure" browsers. In particular, we traced 9% of Tor
streams carried by our instrumented exit nodes. Using BitTorrent as the
insecure application, we design two attacks tracing BitTorrent users on Tor. We
run these attacks in the wild for 23 days and reveal 10,000 IP addresses of Tor
users. Using these IP addresses, we then profile not only the BitTorrent
downloads but also the websites visited per country of origin of Tor users. We
show that BitTorrent users on Tor are over-represented in some countries as
compared to BitTorrent users outside of Tor. By analyzing the type of content
downloaded, we then explain the observed behaviors by the higher concentration
of pornographic content downloaded at the scale of a country. Finally, we
present results suggesting the existence of an underground BitTorrent ecosystem
on Tor
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