The tag has a clear tag wiki excerpt:

A puzzle concerning techniques for secure communication in the presence of (hostile) third parties. Do NOT use this for simple "crack the code" problems; use [cipher] instead.

(I'm the one who added that last sentence, but the edit history shows that the scope was clear the whole time)

However, this tag is very, very misused. Every so often I remember and edit it out of a couple questions, but I daren't do too many at a time for fear of flooding the homepage. People see the tag name, think "encryption", and use it where it doesn't belong. For a rough estimate: out of 146 questions (as of writing), 71 are also tagged with . Now, a few of those will be legitimate, but there are also some which should have but instead only have , which balances out, considering that it is rare for a puzzle to legitimately concern both the method of message transmission and the encoding of the message itself.

There are fun and thought-provoking cryptography puzzles out there! There's the classic padlocked box puzzle where the answer is applying the concept of public-key cryptography, there's sheriffs with tapped phones who have to find their shared suspect, there's testing if numbers are different without revealing the numbers in question. The answers are methods/algorithms for communication, not methods of en/decryption. Personally, I find these much more interesting than the endless slog of "crack this code" puzzles. But they're getting drowned out in their own tag.

(There's even this question titled "Cryptography puzzle", with only the tag, which is... a decode-the-word puzzle.)

Can anything be done about this beyond editing the tag out over and over? Is there another name that would work? Are there enough people who care that we could educate every misuser on-sight, as we currently (mostly successfully) do with ? In essence, is there a way to save from the invading kingdom of ?

  • 5
    $\begingroup$ I wish updating the tags of a question wouldn't automatically bump it. $\endgroup$ Commented Dec 27, 2022 at 14:33
  • $\begingroup$ I actually have a quick question if that's okay: What is "(hostile) third parties" supposed to mean? IMO it doesn't really make that much sense. $\endgroup$
    – CrSb0001
    Commented Apr 19 at 14:51
  • 1
    $\begingroup$ @CrSb0001 See the classic padlocked box problem. While you're sending messages, someone can watch, where you don't want that someone to be able to access (all) information being shared. That someone might even be the other people you're communicating with, if you want to communicate some piece of information but not others. $\endgroup$
    – bobble
    Commented Apr 19 at 17:05

1 Answer 1


I have slowly (very slowly; it's April 2024 here) gone through the list of puzzles. All the ones which should have been have been edited. Only 17 true cryptography puzzles remain.

Hopefully the situation never gets so bad again.


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