Crypto is from greek word Kryptos which means hidden, secret. Our category Crypto is directly related with cryptography. Cryptography in our category is also close related with encryption. Easy explanation is: convertion of readable text into nonsense. There are a lot of methods how to encrypt/decrypt the messages or easily can be invented new method. Or just to modify existing one.
For all of you which do not know how to start and what is cryptography about, at the begining you can start to read someting about ASCII. Or some history about Cryptography.
All improovments of intellect has got the base in free time.