The question What is a Pedersen commitment? was closed as off-topic, with justification that is is a "Requests for literature, software or similar recommendations", when I do not see that it is.

I understand that perhaps we want to exclude overly basic/vague/broad questions like "what is a bit?". But when the term is crypto-specific and not widely known, do we want to exclude the question, assuming that it is not a duplicate?

  • $\begingroup$ I agree largely with the answers of Maeher and forest. I do however think that there is a technical difficulty in the sense that answers basically become Wikipedia pages, with fewer editing capabilities. Closing them after the question is answered only makes this situation worse though. If you're willing to write Wiki pages in MarkDown I won't be stopping you :) $\endgroup$ – Maarten Bodewes Dec 11 '18 at 10:46

I would agree with you, that questions like this should generally be on-topic. The specific question is actually quite bad. It shows a severe lack of research, as the author did not even seem to realize that "commitments" are a more general concept. This meant that — without realizing — they basically asked two questions in one. Namely

What is a commitment scheme?


How do Pedersen Commitments work?

But questions like that with good answers are actually good to have around. They help people who are doing their research, and they can function as convenient references when answering more complex questions where, e.g., knowing what commitments are is helpful for understanding the answer.

  • $\begingroup$ In no way does the author show a lack of knowledge of commitments. How did you conclude this? Perhaps the question has since been edited and the original post had "I don't even know what a commitment is by the way" :) Anyway, that aside, it seems unfair to conclude from a question such as "what is the Riemann Zeta function?", that the asker has no knowledge of functions. $\endgroup$ – Jus12 Apr 15 at 13:54

I believe it should be on-topic, as the implicit question is not just what does the term mean, but how does it work, what is it for, etc. I asked a similar question about the wide-trail design strategy, and it was not closed despite me effectively asking what it means. While that specific question is phrased such that OP may be asking for a literature request, it could be easily edited to hold the same meaning while asking us what it means instead of asking us to find a resource that explains it.

I believe this view is backed up by the fact that you were able to write a useful and descriptive answer without resorting to providing a link-only answer simply giving a literary resource. The reason request questions are off-topic is because they tend to generate lists of links that may or may not be relevant a few months or years down the line. Clearly, you were able to answer the question without links.


To clarify, I had 4 reasons to close vote that one:

  1. Too broad (the usual "What exactly don't you understand?" issue) ,
  2. No description of any research efforts (see our help center on that — "pay it forward" et al),
  3. The body text merely states no answer could be found (hinting at a "where can I read up on them, aka "reference request").
  4. Lack of quality due to 1 - 3 (it's a one-liner repeating the question while not adding any details).

Let's remember how our site works

I'm not going to repeat all the details noted in our help center. I'm merely going to give a heads-up on things.

We always tended to require people to do a minimum of research before asking. When questions are asked, we expect people to describe research efforts and/or where exactly they got stuck trying to find an answer themselves.

The reason for this is simple: we're a Q&A site! We're not a forum, nor a wiki site, and certainly not a replacement for a search engine.

Want to read up in Peterson commitments? Then do so. There are papers and sites out there handling/explaining/defining them.

If you then get stuck somewhere trying to understand them, tell us what you grasped and what you didn't, and you're bound to get help here.

That's how it worked up until now and how we safeguarded the site from low-quality, no research, one-line questions. I don't think we should change that as it would open the door for hundreds of such one-liner questions. Those would definitely not be asked if appropriate research efforts would have been undertaken before bluntly taking a shortcut by asking here.

But when the term is crypto-specific and not widely known, do we want to exclude the question, assuming that it is not a duplicate?

If you take a look at the question you've linked to, you'll notice it merely states

I couldn't find any answer providing a high-level overview on what Pedersen commitments are or what they are used for.

No reference, no paper mentioned, nothing. Also, there is "no problem to be solved" (as the help center states somewhere when talking about how to write a good question). It practically asks for a TLDR or pointers to such, probably to skip own research efforts.

We have other questions at this site asking similar things — and they are all on-topic as they contain research effort descriptions, links to papers, or at least a "I grasped X but got stuck at Y".

So, wrapping this up: generally such questions are on-topic — assuming they do not lack quality, research efforts, et al.

The example you point to is a bad one as it is a one-liner not meeting a single perquisite.

Now , OP of the linked question can still save his/her question and pull it on-topux by editing it… but up until now, that did not happen.


As described above, the linked example question is a bad example as it is low quality and — according to our help center — a so called "bad question". Therefore, I keep my vote as-is.

But generally, questions about specific cryptographic terms are on-topic — assuming they do not lack quality, research efforts, etc.

Note Bene

Of course, other users are free to disagree and vote to reopen… but before doing so, take a minute to think about the consequences. After all, allowing such low quality, one-line questions would contradict the descriptions contained in our help center, and it certainly contradicts how we've handled such questions ever since our site came out of beta.

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    $\begingroup$ The choice you have been facing is exactly why I'm not candidate for being a moderator (despite desperately wanting the privilege of editing my comments past 5 minutes)! Recently I have even stopped to vote for closing RSA questions that I think should be closed (unless I'm the fifth to vote), because that closes them immediately and I'm seldom sure of my judgment on these things. $\endgroup$ – fgrieu Dec 11 '18 at 12:20
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    $\begingroup$ @fgrieu The only real annoyance of being a mod is indeed that - when you drop a mod hammer vote like I did in the example Q - you always have to expect having to write a small book explaining your reasoning. I'm not going to miss that at all. OTOH, I'll dearly miss being able to correct my typos after a few minutes. Soon, we'll both be in the same boat again when it comes to that. ;) $\endgroup$ – e-sushi Dec 11 '18 at 12:28
  • $\begingroup$ (1) is a reason to vote to close. (Whether the question is too broad or not is to some extent subjective, but if it is too broad then closing is the correct action.) (2) is not a reason to close, but it's a reason to downvote. (3) is not a reason to close, but it's a reason to edit. $\endgroup$ – Gilles Dec 12 '18 at 8:19
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    $\begingroup$ @gilles As noted, that editing (3) would need to be done by OP, as onpy he/she can describe his/her research efforts and/or where he/she got stuck. We can't edit a question when we have to guess. (In the end, any edit based in guesses would be like asking a new question.) Besides that, reference requests (3) are clearly off-topic as the close reason provided explains. So, in contrast to your understanding of things it is a valid close reason according to our help center and provided close-vote popup text with according selection option. $\endgroup$ – e-sushi Dec 12 '18 at 22:51
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    $\begingroup$ @fgrieu Note that your hammer only applies if you vote to close as a duplicate, it doesn't apply to any other VTC reason and also gives you a reopen hammer for RSA-tagged questions closed as duplicates $\endgroup$ – SEJPM Dec 17 '18 at 8:25
  • $\begingroup$ @SEJPM: I had noticed that my RSA close hammer also works to reopen, but did not knew the important tidbit that it's restricted to duplicate. Good to know one's tools power to use it wisely, like in D&D. $\endgroup$ – fgrieu Dec 17 '18 at 8:58
  • $\begingroup$ @fgrieu rolls dice ;) $\endgroup$ – e-sushi Dec 17 '18 at 15:13

I believe they should be on topic, but for slightly different reasons as I see value in reference requests. One of the challenging things about cryptography is that many of the terms are specific to the field. I often find that terms that we used in mathematics and quantum mechanics have very different colloquial definitions in cryptography and it's taken me a long time to learn how to "correctly ask a question".

Another note, we do have tags for "literature" and "reference requests", which is probably because things in cryptography are much more difficult to find than other topics that I've come across. Part of this is most likely due to what I describe above, which is people have not agreed on the lexicography of cryptography. When I see a question closed due to a literature or reference request, it makes me wonder why we even have those tags if it is indeed a valid question. On more than one occasion, there are notes such as "because I was at that conference", and the proceeding weren't necessarily available: poncho for AES, me for NIST 8114, etc. For these reasons, I see value in reference request, even at the risk of them going out of date.

  • $\begingroup$ I kind of agree on the topic of reference requests. However, our sister sites all have the same policy, this is more a SE-broad thing. As for the reference request (tag), it is discussed here. You can see an explanation of a term as an "open ended reference request", I guess. $\endgroup$ – Maarten Bodewes Dec 12 '18 at 23:40

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