traffic analysis | Tor Blog

New low cost traffic analysis attacks and mitigations

Recently, Tobias Pulls and Rasmus Dahlberg published a paper entitled Website Fingerprinting with Website Oracles.

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A Critique of Website Traffic Fingerprinting Attacks

Website traffic fingerprinting is an attack where the adversary attempts to recognize the encrypted traffic patterns of specific web pages without using any other information.

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Experimental Defense for Website Traffic Fingerprinting

Updated 09/05/2011: Add link to actual

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Tor’s Bug Smash Fund: Year Two!

The Bug Smash Fund is back for its second year!

New Release: Tor Browser 10.0a4

Tor Browser 10.0a4 is now available from the Tor Browser Alpha download page and also from our

New Release: Tor Browser 9.5.3

Tor Browser 9.5.3 is now available from the Tor Browser download page and also from our

New alpha release: Tor 0.4.4.3-alpha

There's a new alpha release available for download. If you build Tor from source, you can download the source code for 0.4.4.3-alpha from the download page on the website. Packages should be available over the coming weeks, with a new alpha Tor Browser release by mid-August.

Remember, this is an alpha release: you should only run this if you'd like to find and report more bugs than usual.

Tor 0.4.4.3-alpha fixes several annoyances in previous versions, including one affecting NSS users, and several affecting the Linux seccomp2 sandbox.

Changes in version 0.4.4.3-alpha - 2020-07-27

Major features (fallback directory list):
- Replace the 148 fallback directories originally included in Tor 0.4.1.4-rc (of which around 105 are still functional) with a list of 144 fallbacks generated in July 2020. Closes ticket 40061.
Major bugfixes (NSS):
- When running with NSS enabled, make sure that NSS knows to expect nonblocking sockets. Previously, we set our TCP sockets as nonblocking, but did not tell NSS, which in turn could lead to unexpected blocking behavior. Fixes bug 40035; bugfix on 0.3.5.1-alpha.