Help us define our scope by writing the FAQ?

Question

As you probably know, all stackexchange sites have a FAQ. What you might not know is that the community can edit part of it through their moderators. Specifically, we can edit this bit:

What kind of questions can I ask here?

Crypto - Stack Exchange is for software developers, mathematicians and others interested in cryptography.

_{(Actually, without the section title. We can add more sections (with new titles) here, but the part from What kinds of question should I not ask here onwards is not changeable.)}

Currently, this part doesn't say much, as you can see. This is a valuable opportunity for us to have a place where our scope is defined. For example, the programmers FAQ has a lot of detail about what constitutes a good question and what does not - including a nice graphic.

So, what do we want to put in ours? I suggest an approach that goes something like this:

1. We draft some examples in this meta question. Post your draft as an answer.
2. We vote.
3. We come up with a final(ish) version.
4. Your moderators copy and paste.

Of course, I'm fully expecting this process will take time and of course, as we go along we may want to change our FAQ. I know. I just think we should get the ball rolling.

Things to consider in our FAQ:

• This question: Are questions on specific implementations on topic?
• Questions like this: How can we reason about the cryptographic capabilities of code-breaking agencies like the NSA or GCHQ? and this: https://crypto.stackexchange.com/questions/547 I initially closed the first one but there was a lot of support for it to be asked, so I re-opened it. The second one I think isn't a great fit here... but crucially it isn't just my, or any moderator's, decision. It's yours.

Defining the FAQ is important. At the moment, only 7 users have close vote privileges, so it would take most of them (or a moderator) to close a question. Until such a time as it becomes about votes, the more community guidance on what we (the whole) want, the better. When it does become about votes, we have something we can all use to be consistent.

Feel free to edit this question, make suggestions for the process and of course, answer!

Also, remember we have a chat room where discussions can be had. Please feel free to join us in there!

Answer 1

Here's my draft of a FAQ. I've written it with the "in my head" version of our policy; feel free to debate that elsewhere and I'll update this as and when. If you want to improve it, feel free to, if you want to have a go at drafting your own version, please do that too.

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What kind of questions can I ask here?

Crypto - Stack Exchange is for software developers, mathematicians and others interested in cryptography.

Cryptography Stack Exchange is for asking questions about the mathematics and properties of cryptographic systems, their analysis ("cryptanalysis") and subsidiary topics that generally make up cryptology, such as random number generation. As such, we welcome questions on topics such as:

• Asymmetric and symmetric cryptographic algorithms.
• Cryptographic protocols.
• Cryptanalysis techniques.
• Hash functions, hashing.
• Entropy and information theory.
• Random number generation.

Do we accept basic level/homework questions?

Yes, we do. However, please try to provide an indication of what you are not understanding/need clarification on. If you have just written out your assignment, it is highly likely your question will be closed. You might want to read this article on writing the perfect question – originally for Stack Overflow, but relevant here too.

Do we accept questions asking for cryptanalysis of your cipher (hash function, ...) design?

That depends. Questions about cipher design (yours or someone else's) are fine as long as they are precise and specific - so we encourage you to break your cipher down where possible into reasonably scoped and well focused parts, so you get well focused answers. If you post a long and complicated scheme, it is likely to run into difficulties as it is hard for one answer to address all of the potentially relevant points.

Can I get data analysed here? Can I challenge people to decode something?

No, questions like 'can you decrypt this particular piece of ciphertext' are not useful. However, if you do have specific questions about the design of a cipher, its cryptanalysis or a cryptanalytic result, these are great questions.

I'm confused as to where my question belongs; there are so many sites!

There are lots of places in the Stack Exchange network to ask your question; don't worry too much about getting it wrong, because it can always be migrated to the right place. That said, it is useful to provide a general guide here:

• If your question is about using cryptographic software in your application, you probably need Stack Overflow.
• If your question is about mathematics generally, without any cryptographic element, you'll get an excellent answer on Mathematics.
• If your question is about cryptographic policy within your organisation, implementation and practical usage considerations, you probably are looking for Security.
• If your question is about usage of a specific cryptographic software, see Super User.
• If your question involves large amounts of research and a lot of computer science, you might find CS Theory an appropriate place to ask. Please bear in mind their FAQ and policy on non-research level questions.

I'm still stuck between Security.SE and Crypto.SE.

The rule of thumb, here, being that you should post to crypto.SE if you want to understand the internals, and to security.SE if you want to know what you should do now.