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path: root/Documentation/technical/hash-function-transition.txt
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2021-06-14*: fix typos which duplicate a wordAndrei Rybak
Fix typos in documentation, code comments, and RelNotes which repeat various words. In trivial cases, just delete the duplicated word and rewrap text, if needed. Reword the affected sentence in Documentation/RelNotes/1.8.4.txt for it to make sense. Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05doc: use https linksThomas Ackermann
Use only https links for lore.kernel.org. Signed-off-by: Thomas Ackermann <th.acker@arcor.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05doc hash-function-transition: move rationale upwardsThomas Ackermann
Move rationale for new hash function to beginning of document so that it appears before the concrete move to SHA-256 is described. Remove some of the details about SHA-1 weaknesses and add references to the details on how the new hash function was chosen instead. Signed-off-by: Thomas Ackermann <th.acker@arcor.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05doc hash-function-transition: fix incomplete sentenceThomas Ackermann
Signed-off-by: Thomas Ackermann <th.acker@arcor.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05doc hash-function-transition: use upper case consistentlyThomas Ackermann
Use upper case consistently in Document History. Signed-off-by: Thomas Ackermann <th.acker@arcor.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05doc hash-function-transition: use SHA-1 and SHA-256 consistentlyThomas Ackermann
Use SHA-1 and SHA-256 instead of sha1 and sha256 when referring to the hash type. Signed-off-by: Thomas Ackermann <th.acker@arcor.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05doc hash-function-transition: fix asciidoc outputThomas Ackermann
Asciidoc requires lists to start with an empty line and uses different characters for indentation levels ("-", "*", "**", ...). For special symbols like a dash "--" has to be used and there is no double arrow "<->", so a left and right arrow "<-->" has to be combined for that. Lastly for verbatim output a newline followed by an indentation has to be used. Fix asciidoc output for lists, special characters and verbatim text while retaining the readabilty of the original text file. Signed-off-by: Thomas Ackermann <th.acker@arcor.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-14docs: fix step in transition planbrian m. carlson
One of the required steps for the objectFormat extension is to implement the loose object index. However, without support for compatObjectFormat, we don't even know if the loose object index is needed, so it makes sense to move that step to the compatObjectFormat section. Do so. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06Merge branch 'jk/lore-is-the-archive'Junio C Hamano
Doc update for the mailing list archiving and nntp service. * jk/lore-is-the-archive: doc: replace public-inbox links with lore.kernel.org doc: recommend lore.kernel.org over public-inbox.org
2019-11-30doc: replace public-inbox links with lore.kernel.orgJeff King
Since we're now recommending lore.kernel.org (and because the public-inbox.org domain might eventually go away), let's update our internal references to use it, too. That future-proofs our references, and sets the example we want people to follow. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-07Documentation: fix a bunch of typos, both old and newElijah Newren
Reported-by: Jens Schleusener <Jens.Schleusener@fossies.org> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-12doc: fix repeated wordsMark Rushakoff
Inspired by 21416f0a07 ("restore: fix typo in docs", 2019-08-03), I ran "git grep -E '(\b[a-zA-Z]+) \1\b' -- Documentation/" to find other cases where words were duplicated, e.g. "the the", and in most cases removed one of the repeated words. There were many false positives by this grep command, including deliberate repeated words like "really really" or valid uses of "that that" which I left alone, of course. I also did not correct any of the legitimate, accidentally repeated words in old RelNotes. Signed-off-by: Mark Rushakoff <mark.rushakoff@gmail.com> Acked-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-07doc hash-function-transition: pick SHA-256 as NewHashJonathan Nieder
From a security perspective, it seems that SHA-256, BLAKE2, SHA3-256, K12, and so on are all believed to have similar security properties. All are good options from a security point of view. SHA-256 has a number of advantages: * It has been around for a while, is widely used, and is supported by just about every single crypto library (OpenSSL, mbedTLS, CryptoNG, SecureTransport, etc). * When you compare against SHA1DC, most vectorized SHA-256 implementations are indeed faster, even without acceleration. * If we're doing signatures with OpenPGP (or even, I suppose, CMS), we're going to be using SHA-2, so it doesn't make sense to have our security depend on two separate algorithms when either one of them alone could break the security when we could just depend on one. So SHA-256 it is. Update the hash-function-transition design doc to say so. After this patch, there are no remaining instances of the string "NewHash", except for an unrelated use from 2008 as a variable name in t/t9700/test.pl. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: brian m. carlson <sandals@crustytoothpaste.net> Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Acked-by: Dan Shumow <danshu@microsoft.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-25doc hash-function-transition: note the lack of a changelogÆvar Arnfjörð Bjarmason
The changelog embedded in the document pre-dates the addition of the document to git.git (it used to be a Google Doc), so it only goes up to 752414ae43 ("technical doc: add a design doc for hash function transition", 2017-09-27). Since then I made some small edits to it, which would have been worthy of including in this changelog (but weren't). Instead of amending it to include these, just note that future changes will be noted in the log. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-28doc hash-function-transition: clarify what SHAttered meansÆvar Arnfjörð Bjarmason
Attempt to clarify what the SHAttered attack means in practice for Git. The previous version of the text made no mention whatsoever of Git already having a mitigation for this specific attack, which the SHAttered researchers claim will detect cryptanalytic collision attacks. I may have gotten some of the nuances wrong, but as far as I know this new text accurately summarizes the current situation with SHA-1 in git. I.e. git doesn't really use SHA-1 anymore, it uses Hardened-SHA-1 (they just so happen to produce the same outputs 99.99999999999...% of the time). Thus the previous text was incorrect in asserting that: [...]As a result [of SHAttered], SHA-1 cannot be considered cryptographically secure any more[...] That's not the case. We have a mitigation against SHAttered, *however* we consider it prudent to move to work towards a NewHash should future vulnerabilities in either SHA-1 or Hardened-SHA-1 emerge. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-28doc hash-function-transition: clarify how older gits die on NewHashÆvar Arnfjörð Bjarmason
Change the "Repository format extension" to accurately describe what happens with different versions of Git when they encounter NewHash repositories, instead of only saying what happens with versions v2.7.0 and later. See ab9cb76f66 ("Repository format version check.", 2005-11-25) and 00a09d57eb ("introduce "extensions" form of core.repositoryformatversion", 2015-06-23) for the relevant changes to the setup code where these variables are checked. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-28technical doc: add a design doc for hash function transitionJonathan Nieder
This document describes what a transition to a new hash function for Git would look like. Add it to Documentation/technical/ as the plan of record so that future changes can be recorded as patches. Also-by: Brandon Williams <bmwill@google.com> Also-by: Jonathan Tan <jonathantanmy@google.com> Also-by: Stefan Beller <sbeller@google.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>