There are many methods of encrypting information. And even different methods as to whether you are encrypting information to be stored in a file or being used to encrypt information that is being exchanged between computers or streaming film and video to remote screens. This infographic summarises the commonest encryption algorithms and methods that they are used for. Some of the algorithms are used to exchange secret keys (Elliptic Curve) whilst others (AES) are used to encrypt information in files. The commonest and simplest cipher is the Caesar cipher which works by substituting a different letter for the one being used (A becomes F, B becomes G and so on).
Infographic Source: Lock Lizard