anonymity

The Security and Privacy Day is a biannual workshop sponsored by the greater New York City area computer security research community for bringing area researchers together, fostering multi-institutional collaborations, and discussing and exchanging our ideas and experiences with security and privacy research. We invite you to attend and encourage you to submit a proposal for a poster or demonstration. Registration is required, if you plan to attend.

The 2008 S&P Day is hosted by Stony Brook University on Friday, May 30, 2008. While registration is free please register here by May 25.

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Simulating a Global Passive Adversary for Attacking Tor-like Anonymity Systems
We present a novel, practical, and effective mechanism for identifying the IP address of Tor clients. We approximate an almost-global passive adversary (GPA) capable of eavesdropping anywhere in the network by using LinkWidth, a novel bandwidth-estimation technique. LinkWidth allows network edge-attached entities to estimate the available bandwidth in an arbitrary Internet link without a cooperating peer host, router, or ISP. By modulating the bandwidth of an anonymous connection (e.g., when the destination server or its router is under our control), we can observe these fluctuations as they propagate through the Tor network and the Internet to the end-user's IP address. Our technique exploits one of the design criteria for Tor (trading off GPA-resistance for improved latency/bandwidth over MIXes) by allowing well-provisioned (in terms of bandwidth) adversaries to effectively become GPAs. Although timing-based attacks have been demonstrated against non-timing-preserving anonymity networks, they have depended either on a global passive adversary or on the compromise of a substantial number of Tor nodes. Our technique does not require compromise of any Tor nodes or collaboration of the end-server (for some scenarios). We demonstrate the effectiveness of our approach in tracking the IP address of Tor users in a series of experiments. Even for an under-provisioned adversary with only two network vantage points, we can accurately identify the end user (IP address) in many cases. Furthermore, we show that a well-provisioned adversary, using a topological map of the network, can trace-back the path of an anonymous user in under 20 minutes. Finally, we can trace an anonymous Location Hidden Service in approximately 120 minutes.

If only it wasn't the same time as World Science Festival's talk on quantum physics.

There have been a lot of questions today about just what the recent Debian OpenSSL flaw means for Tor clients. Here's an attempt to explain it in a bit more detail.

No TOR destinations are hidden from Bruce Schneier.

Privacy no longer can mean anonymity, says Donald Kerr, the principal deputy director of national intelligence. Instead, it should mean that government and businesses properly safeguard people's private communications and financial information.

In other words, your life is no longer private, it's all known and documented in dozens if not hundreds of places by the government and by the corporations (which are seeming more and more like one big entity all the time) and we're all supposed to trust them to keep it all secure.