While reviewing a post in the Sandbox, I went searching to try to find some duplicates. I recalled a previous challenge that was tagged cipher: 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 cryptography. 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?