# How to Make Non-too-broad Cipher Puzzles?

// I'm not sure whether this is better to be asked here or on meta.

Unfortunately, many people (or at least my friends) agree that puzzles are plainly just "random guessing" in a sense that they need some random approach to solve puzzles. Sure I may convince them that it's not totally correct as we may need some logical approach or creative thinking to uncover the mystery.

But, whenever they say about ciphers, my explanation seems useless and can't make them satisfied. I guess because most of ciphers puzzles are... too-broad (?).

1. Are cipher puzzles indeed broad?
2. [Meta] When are cipher puzzles here in PSE classified as broad (or not)?
3. How to make non-too-broad cipher puzzles in general?
• Puzzle creation is on-topic here and not meta. Except your question #2 maybe, but I think "too broad" is the wrong term anyway. My sense is that cipher puzzles, even bad ones, almost always have a single objectively correct answer. It's just that this answer can only be found by trying a whole bunch of random tedious things until one of them works. – deep thought Jan 20 '19 at 2:03
• @deep thought, ah exactly, good point. If it's not too broad.. are cipher puzzles actually.. enigmatic puzzle then? Maybe yes it's true, and it makes more sense in such way.. hmm.. – athin Jan 20 '19 at 15:17

The issue with a cipher puzzle is generally not being "too broad", but being solvable at all.

A cipher usually isn't too broad. As long as it's not a one-time pad, it probably has a single clear best decoding. The problem with ciphers is that they are intentionally made to be hard to solve. The point of most ciphers is that nobody can decode them easily. So you end up with two options:

• The "ciphers" are ones that are meant to be decoded (Morse, Braille, ASCII binary/hex/decimal, rot13). In this case, the puzzle is probably just a bunch of these chained together, and it is very boring.
• The ciphers are ones that are not meant to be decoded (like most ciphers). In this case, the puzzle is probably impossible or very difficult without a key, and easy with one. Either way, it's probably not fun.

So what's the solution to this problem? I see two main ways to do it:

• Make a new cipher. This is difficult, because you have to make it solvable by hiding hints somehow: maybe a strange letter distribution, maybe an image of the "inner workings", maybe something else altogether. Even if you do succeed at this, you'll likely turn some people away: I know I generally don't bother with puzzles that just have large blocks of nonsense, unless I can see that they're carefully thought out.
• Use an "easy" cipher, and hide it in a clever way. Maybe all the punctuation in a paragraph is Morse code. Maybe the solution to a Minesweeper puzzle is Braille. Maybe a collection of coffee cups is secretly binary.
• Ah, this answer pretty sums up the things nicely; the last point enlightened me the most. Thanks! :) – athin Jan 24 '19 at 23:34

First of all, this should likely be moved to the meta site, like you suggested.

Second, I think that a cipher puzzle is generally acceptable if it's reasonably solve-able with a pencil, paper, and possibly an inexpensive calculator.

Simple mono-alphabetic substitution can be solved via frequency analysis (pencil and paper). Slightly more advanced ciphers (like my own question that I currently have a bounty on) still have patterns that can be identified through various methods. Hints as to the method of encryption may make the puzzle more "attractive".

It's difficult to say exactly where the distinction lies, but I think it's safe to say that if you need some sort of computer program to solve it, it's too hard for this site.

• Hmm, ok I got your point that the cipher should be solved by hand. Does it mean "usual" ciphers like Vigenere, Base64 which used a program are not a good one? – athin Jan 19 '19 at 10:13
• I don't know about Base64, but the Vigenere can be solved by hand, assuming persistence and a fairly short key. Those would definitely be on the hard end, though, IMO. And again, I'm not a mod; the line I drew was just based on what seemed like common sense to me. I do believe that we have a cryptography stack on this network; perhaps (can't guarantee) they would take harder puzzles. @athin – Brandon_J Jan 19 '19 at 15:24

I think that this thinking is all depends upon the situations. A same thing might be bored for someone but may be interesting for the otherone. A same thing might be bored at some time but may be interesting at some other time. In my opinion all human emotions, reactions and feelings are not constant. They varied time to time, situations to situations and persons to persons.

• I agreed that they may depend on personal taste, but I'm more asking whether the ciphers are indeed broad or not as they may be solvable but boring, or even not solvable (?) but interesting. How to create an interesting non-broad cipher puzzle? – athin Jan 19 '19 at 10:15