From: Zooko O'Whielacronx Date: Tue, 25 Mar 2008 18:22:41 +0000 (-0700) Subject: docs: document the private/convergence configuration file X-Git-Url: https://git.rkrishnan.org/specifications/banana.xhtml?a=commitdiff_plain;h=29b844efaf7f2eeee17260016ff69292f124ca97;p=tahoe-lafs%2Ftahoe-lafs.git docs: document the private/convergence configuration file --- diff --git a/docs/configuration.txt b/docs/configuration.txt index 907d0a8e..233392c9 100644 --- a/docs/configuration.txt +++ b/docs/configuration.txt @@ -84,6 +84,28 @@ private/root_dir.cap (optional): The command-line tools will read a directory cap out of this file and use it, if you don't specify a '--dir-cap' option or if you specify '--dir-cap=root'. +private/convergence (automatically generated): An added secret for encrypting +immutable files. Everyone who has this same string in their private/convergence +file encrypts their immutable files in the same way when uploading them. This +causes identical files to "converge" -- to share the same storage space since +they have identical ciphertext -- which conserves space and optimizes upload +time, but it also exposes files to the possibility of a brute-force attack by +people who know that string. In this attack, if the attacker can guess most of +the contents of a file, then they can use brute-force to learn the remaining +contents. + +So the set of people who know your private/convergence string is the set of +people who converge their storage space with you when you and they upload +identical immutable files, and it is also the set of people who could mount such +an attack. + +The content of the private/convergence file is a base-32 encoded string. If the +file doesn't exist, then when the Tahoe client starts up it will generate a +random 256-bit string and write the base-32 encoding of this string into the +file. If you want to converge your immutable files with as many people as +possible, put the empty string (so that private/convergence is a zero-length +file). + == Node State ==