Not infrequently, we receive questions asking for help (meaning a solution) with finding the preimage for a hash function. Typically they ask for help "decrypting" a given hash value.

The available reasons for closing an off-topic question are:

  • Requests for analyzing ciphertext or reviewing full cryptographic designs are off-topic, as the results are rarely useful to anyone else and/or would be too long for this site.

  • Requests for literature, software or similar recommendations are off-topic here. For details, see: Do we want “literature recommendations” and similar “list/subjective questions”?

  • Programming questions are off-topic even if you are writing or debugging cryptographic code. Unless your question is specifically about how the cryptographic algorithm, protocol or side-channel (mitigation) works, you should look into asking on Stack Overflow instead.

  • This question belongs on another site in the Stack Exchange network

  • Other (add a comment explaining what is wrong)

With most of the pertinent questions that are closed citing the "analyzing ciphertext" reason.

As many users have noted many times on the site, hashing is not encrypting, the output of a hash function is not a "ciphertext", computing a preimage is not "decrypting", etc.

Request

Could we have "requests to find hash preimages" included in the off-topic close reason that mentions analyzing ciphertext and reviewing full cryptographic designs? The proposed text would read something like:

Requests for analyzing ciphertext, finding hash preimages, or reviewing full cryptographic designs are off-topic, as the results are rarely useful to anyone else and/or would be too long for this site.

This is a minor change that would simply make the close reason more accurate.

Please vote on your preferred formulation during the next 7 days and / or add your own.

As a reminder:
+1 -> "I really like this formulation"
+0 -> "Meh, it's ok I guess"
-1 -> "I really dislike this formulation and don't want to see it"

  • Maybe, there must be area51 for such questions. Usually, if not answered here, or at the same time, people write these questions at different places. Also, in security.stackexchange, there are talks about hash finding stuff as far as I can see. – kelalaka Oct 7 at 10:35
  • 1
    More often than not such questions simply have no answer or lack the necessary context to even make educated guesses. So such a site would have a very hard time generating quality content that is also useful to others. – SEJPM Oct 7 at 12:23
  • The time period is over and e-sushi's suggestion has been implemented. – SEJPM Oct 14 at 16:31
up vote 8 down vote accepted

Requests for analyzing ciphertext, finding hash preimages, identifying or decoding some code, or even reviewing full cryptographic designs are off-topic, as the results are rarely useful to anyone else and/or would be too long for this site.


This one takes the new hash preimage suggestion and additionally adds one more to the bucket which we tend to get and close frequently: "identifying or decoding code".

This would not only wrap up hash preimages but also alike yet non-preimage-related questions like (examples linked)

as well as

The formulation "some code" should be generic enough to even catch outliers.

  • Please remind ourselves that this is a bit of a trick; it contains two rather different close reasons: analyzing "code" ("encoded results"?) -> rarely useful to anyone else and analyzing cryptographic designs -> too long (and results in extended discussion). Maybe we can split it or - if that's not possible for SE - reword it somewhat. – Maarten Bodewes Oct 8 at 15:07
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    @MaartenBodewes We can only have three custom close reasons, so splitting isn't really an option for now (unless you want to redecide on all 3). The idea behind having these merged was that these questions are "too localized" but the current / sushi's wording is more easily understood. – SEJPM Oct 8 at 16:48

Requests for analyzing ciphertext, finding hash preimages, or reviewing full cryptographic designs are off-topic, as the results are rarely useful to anyone else and/or would be too long for this site.


This is the (new) formulation provided in the question.

  • This has my upvote (I can't vote on my own posts). – SEJPM Oct 7 at 12:30
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    I think e-sushis suggestion is a bit more of a catch-all. It expands the text even more, but close-voters should have enough rep to get it, and if the question gets closed I presume that the user will want to carefully read it anyway. – Maarten Bodewes Oct 8 at 15:04

Requests for analyzing ciphertext or reviewing full cryptographic designs are off-topic, as the results are rarely useful to anyone else and/or would be too long for this site.


This is the old close reason, without the explicit new "hash preimage clause".

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