This is a site on Cryptography, but in the site, I couldn't find a definition of Cryptography. How will we define that?
Literally translated, cryptography is Greek for "hidden writing".
Wikipedia defines old cryptography as "synonymous with encryption", while modern cryptography as "heavily based on mathematical theory and computer science practice".
Which (or both?) of these is this site on? That might also be nice to have in the Tour, and/or the help center.
If you have a different definition, or I missed something in my research, answer with that as well. The point is to get this cleared up, and to keep improving this site.