Base64 decode encode

Base64 is a byte sequence of 8-bit padded ascii in mime.

URLencode decode encode

Tyically used for passing strings and variables between web pages

ROT13 encode

Rotates the characters 13 places. Since the basic latin1 alphabet has 26 characters, performing rot13 on a string encrypts it. Do it twice, and it's decrypted.

HTMLentities decode encode

Encodes or decodes all characters that have a HTML equivalent entity.