From: david-sarah Date: Sun, 24 Oct 2010 23:42:59 +0000 (-0700) Subject: docs/known_issues.rst: Add section on traffic analysis. Fix URL for current version... X-Git-Tag: trac-4800~37 X-Git-Url: https://git.rkrishnan.org/provisioning?a=commitdiff_plain;h=5528af0524e4637caa5545d1f57e7b31e37495ea;p=tahoe-lafs%2Ftahoe-lafs.git docs/known_issues.rst: Add section on traffic analysis. Fix URL for current version of file. --- diff --git a/docs/known_issues.rst b/docs/known_issues.rst index 58be6ab9..515624f3 100644 --- a/docs/known_issues.rst +++ b/docs/known_issues.rst @@ -17,7 +17,7 @@ Overview Below is a list of known issues in recent releases of Tahoe-LAFS, and how to manage them. The current version of this file can be found at -http://tahoe-lafs.org/source/tahoe-lafs/trunk/docs/known_issues.txt +http://tahoe-lafs.org/source/tahoe-lafs/trunk/docs/known_issues.rst If you've been using Tahoe-LAFS since v1.1 (released 2008-06-11) or if you're just curious about what sort of mistakes we've made in the past, then you might @@ -200,3 +200,30 @@ Known issues in the FTP and SFTP frontends These are documented in docs/frontends/FTP-and-SFTP.txt and at . + + +Traffic analysis based on sizes of files/directories, storage indices, and timing +--------------------------------------------------------------------------------- + +Files and directories stored by Tahoe-LAFS are encrypted, but the ciphertext +reveals the exact size of the original file or directory representation. +This information is available to passive eavesdroppers and to server operators. + +For example, a large data set with known file sizes could probably be +identified with a high degree of confidence. + +Uploads and downloads of the same file or directory can be linked by server +operators, even without making assumptions based on file size. Anyone who +knows the introducer furl for a grid may be able to act as a server operator. +This implies that if such an attacker knows which file/directory is being +accessed in a particular request (by some other form of surveillance, say), +then they can identify later or earlier accesses of the same file/directory. + +Observing requests during a directory traversal (such as a deep-check +operation) could reveal information about the directory structure, i.e. +which files and subdirectories are linked from a given directory. + +Attackers can combine the above information with inferences based on timing +correlations. For instance, two files that are accessed close together in +time are likely to be related even if they are not linked in the directory +structure. Also, users that access the same files may be related to each other.