{"id":39,"date":"2006-04-24T00:14:18","date_gmt":"2006-04-24T04:14:18","guid":{"rendered":"http:\/\/blogs.law.harvard.edu\/zeroday\/2006\/04\/24\/noisechain-insures-no-single-person-i"},"modified":"2007-10-01T16:25:12","modified_gmt":"2007-10-01T20:25:12","slug":"noisechain-insures-no-single-person-is-provably-responsible-of-host","status":"publish","type":"post","link":"https:\/\/archive.blogs.harvard.edu\/zeroday\/2006\/04\/24\/noisechain-insures-no-single-person-is-provably-responsible-of-host\/","title":{"rendered":"Noisechain ensures &#8220;no single person is provably responsible of hosting\/distributing a given file.&#8221;"},"content":{"rendered":"<p><a name=\"a49\"><\/a><\/p>\n<p>This is a really interesting technology that makes it difficult (if not impossible) to determine who is hosting a particular file.  After reading the latest <a href=\"http:\/\/www.politechbot.com\/2006\/04\/24\/congress-readies-new\/\"> changes to the DMCA <\/a> we may really need something like this.  I&#8217;ll blog more about those changes next.  <\/p>\n<pre>\r\nAn anonymous person will use Noisechain, to break the 'FILE' into 5 parts. Here's what \r\nNoisechain does. XOR is a commutative operator, so we need few parenthesis:\r\n\r\n   1. generate 4 files: A, B, C, D, with completely random data in each.\r\n   2. calculate X = (A XOR B XOR C XOR D) which is random; see (b)\r\n   3. calculate E = (FILE XOR X), which is random; see (b)\r\n   4. we now have A, B, C, D, E, which are all random, **but** have the property: (A XOR B \r\nXOR C XOR D XOR E) = X XOR E = FILE\r\n   5. permute A, B, C, D, E randomly, to lose track of which come from step '1', and which \r\ncomes from step '3'.\r\n\r\nSo, from a 'test.zip' file, noisechain will output 5 separate files, 'test.zip.[1-5].noise' which \r\ncan then be hosted independently by 5 people.\r\n\r\nOf course, it would be quite stupid to require 5 URLs for downloading the files. That is \r\nwhy, with each 'noise' file, you get a 'chain' file that points to the next URL.\r\n\r\nAnyhow, it is mandatory to download *all* 5 files. If you have only 4 files, you have \r\nrandom data that gives **zero** information about the file. If the 5 people are in different \r\ncountries, it it a nice bonus.\r\n<\/pre>\n<p>update 10\/1\/07: s\/insures\/ensures\/g; <\/p>\n","protected":false},"excerpt":{"rendered":"<p>This is a really interesting technology that makes it difficult (if not impossible) to determine who is hosting a particular file. After reading the latest changes to the DMCA we may really need something like this. I&#8217;ll blog more about those changes next. An anonymous person will use Noisechain, to break the &#8216;FILE&#8217; into 5 [&hellip;]<\/p>\n","protected":false},"author":214,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[274],"tags":[],"class_list":["post-39","post","type-post","status-publish","format-standard","hentry","category-interesting-tech"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/posts\/39","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/users\/214"}],"replies":[{"embeddable":true,"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/comments?post=39"}],"version-history":[{"count":0,"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/posts\/39\/revisions"}],"wp:attachment":[{"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/media?parent=39"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/categories?post=39"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive.blogs.harvard.edu\/zeroday\/wp-json\/wp\/v2\/tags?post=39"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}