While reviewing a post in the Sandbox, I went searching to try to find some duplicates. I recalled a previous challenge that was tagged : Caesar shifting. I didn't think this was a duplicate of the sandboxed challenge, so I examined the other questions tagged cipher. This wasn't very helpful, as there were very few such questions. Eventually I found a more similar question about the Vigenère cipher, which I then tagged with cipher, to make it easier to find again.

This was all fine, until another challenge was posted on the sandboxed question that pointed out it was essentially a duplicate of the Substitution Cipher question. My first thought was to add the cipher tag to this question as well, so I wouldn't miss it again, but then I noticed that the challenge had been tagged with . A good number (over half of the open questions) of the questions tagged with cryptography are about implementing ciphers.

The tag info for these tags is rather lackluster, so I'm not sure if they are meant to imply different things. Neither tag seems to imply that the challenge should be about performing known encryption and decryption, or if the challenge is about making a program that tries to break a cipher, however currently the latter type of challenge are only tagged with cryptography (e.g. this question).

Should the cipher and cryptography tags be merged, or do they mean something different? If they are different, what do they mean and how should they be used?

  • 1
    \$\begingroup\$ Generally a cipher is a specific cryptographic concept/object, so they should be tagged with cryptography and cipher (if applicable). \$\endgroup\$ – Rɪᴋᴇʀ Jun 28 '16 at 14:02
  • 1
    \$\begingroup\$ You honestly think a Caesar cipher is cryptography? :) \$\endgroup\$ – Blue Jun 28 '16 at 15:51
  • \$\begingroup\$ @muddyfish Hey, those things can be hard to figure out! You have to try twenty six different possibilities to be sure. That's just crazy. (More seriously, it does technically meet the criteria, as cryptography includes basic encryption.) \$\endgroup\$ – FryAmTheEggman Jun 28 '16 at 16:03
  • \$\begingroup\$ @muddyfish It is a classical cipher, which is still within the realm of cryptography. \$\endgroup\$ – Mego Jun 28 '16 at 23:55

To me, this is the same concept as an earlier meta post: Let's remove [tag:math]!

is about implementing specific ciphers. It is a subset of . However, there is a lot more to cryptography than the individual ciphers. Cryptosystems are formed by combining one or more ciphers with other algorithms to achieve the desired goal. Often, the specific cipher(s) used don't matter much, so long as they meet the requirements. Thus, a challenge about PGP would be tagged with , but not necessarily , since for each step in the chain (hash, compress, symmetric-key encrypt, public-key encrypt), one of many algorithms can be used, and thus it's more about the system as a whole rather than the individual algorithms/ciphers used.

In short, is a subset of , but there is a lot of stuff that would fall under but not necessarily . Thus, the tags should be kept separate.

  • 1
    \$\begingroup\$ So I was on the fence about this, and I do think this is fine. The main reason I thought it might be better to join them is that there didn't really seem to be much of a use case for the narrower cipher tag. How often will searching through just cipher be much better than cryptography for duplicate finding? Or how often will someone want to answer only cipher questions but not the general cryptography ones? In any case, I assume you then support slowly adding the cipher tag to the ~20 challenges in cryptography that are also about ciphers? \$\endgroup\$ – FryAmTheEggman Jun 29 '16 at 2:56
  • \$\begingroup\$ @FryAmTheEggman In my opinion, the cipher tag should be used for "implement X cipher", "break X cipher", and "make your own cipher" challenges. For the cryptography challenges that don't fall into one of those categories, leave off the cipher tag. The cryptography tag belongs on all cryptography challenges, including those where the cipher tag is appropriate. In addition, the cipher tag info states that it's only for classic ciphers, and that challenges pertaining to modern ciphers should use the encryption tag instead. I'd be in support of adding the cipher tag where appropriate, yes. \$\endgroup\$ – Mego Jun 29 '16 at 9:24

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .