{"id":27812,"date":"2020-01-08T17:00:55","date_gmt":"2020-01-08T22:00:55","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=27812"},"modified":"2020-01-10T13:13:08","modified_gmt":"2020-01-10T18:13:08","slug":"chosen-prefix-collision-for-sha-1","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2020\/01\/08\/chosen-prefix-collision-for-sha-1\/","title":{"rendered":"Chosen-Prefix Collision for SHA-1"},"content":{"rendered":"<p><a href=\"https:\/\/sha-mbles.github.io\">SHA-1 is a Shambles<\/a> (via <a href=\"https:\/\/news.ycombinator.com\/item?id=21979333\">Hacker News<\/a>):<\/p>\n<blockquote cite=\"https:\/\/sha-mbles.github.io\"><p>We have computed the very first chosen-prefix collision for SHA-1. In a nutshell, this means a complete and practical break of the SHA-1 hash function, with dangerous practical implications if you are still using this hash function.  To put it in another way: all attacks that are practical on MD5 are now also practical on SHA-1.  Check our paper <a href=\"https:\/\/eprint.iacr.org\/2020\/014.pdf\">here<\/a> for more details.<\/p><\/blockquote>\n\n<p>See also: <a href=\"https:\/\/www.schneier.com\/blog\/archives\/2020\/01\/new_sha-1_attac.html\">Bruce Schneier<\/a>.<\/p>\n\n<p>Previously:<\/p>\n<ul>\n<li><a href=\"https:\/\/mjtsai.com\/blog\/2017\/02\/23\/sha-1-collision\/\">SHA-1 Collision<\/a><\/li>\n<\/ul>\n\n<p id=\"chosen-prefix-collision-for-sha-1-update-2020-01-10\">Update (2020-01-10): Git has been working on the SHA-1 problem since 2017, but it seems like the default behavior is still to use it. Here&rsquo;s <a href=\"https:\/\/news.ycombinator.com\/item?id=21981596\">some<\/a> <a href=\"https:\/\/stackoverflow.com\/questions\/10434326\/hash-collision-in-git\/43355918#43355918\">information<\/a> on the efforts. A recent <a href=\"https:\/\/lore.kernel.org\/git\/20200108073042.GD1675456@coredump.intra.peff.net\/T\/#t\">post<\/a> on the Git mailing list about the chosen-prefix collision did not generate much interest or a definitive statement.<\/p>","protected":false},"excerpt":{"rendered":"<p>SHA-1 is a Shambles (via Hacker News): We have computed the very first chosen-prefix collision for SHA-1. In a nutshell, this means a complete and practical break of the SHA-1 hash function, with dangerous practical implications if you are still using this hash function. To put it in another way: all attacks that are practical [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"apple_news_api_created_at":"2020-01-08T22:00:57Z","apple_news_api_id":"1d6c06af-0ffa-4e05-85ec-45380bf48d03","apple_news_api_modified_at":"2020-01-10T18:13:12Z","apple_news_api_revision":"AAAAAAAAAAAAAAAAAAAAAA==","apple_news_api_share_url":"https:\/\/apple.news\/AHWwGrw_6TgWF7EU4C_SNAw","apple_news_coverimage":0,"apple_news_coverimage_caption":"","apple_news_is_hidden":false,"apple_news_is_paid":false,"apple_news_is_preview":false,"apple_news_is_sponsored":false,"apple_news_maturity_rating":"","apple_news_metadata":"\"\"","apple_news_pullquote":"","apple_news_pullquote_position":"","apple_news_slug":"","apple_news_sections":"\"\"","apple_news_suppress_video_url":false,"apple_news_use_image_component":false,"footnotes":""},"categories":[2],"tags":[377,31,30,48,1484],"class_list":["post-27812","post","type-post","status-publish","format-standard","hentry","category-technology","tag-git","tag-ios","tag-mac","tag-security","tag-sha-1"],"apple_news_notices":[],"_links":{"self":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/27812","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/comments?post=27812"}],"version-history":[{"count":2,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/27812\/revisions"}],"predecessor-version":[{"id":27835,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/27812\/revisions\/27835"}],"wp:attachment":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/media?parent=27812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/categories?post=27812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/tags?post=27812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}