is one of the oldest known encryption methods. It is very simple - it is just shifting an alphabet. Transformation is termed ROTN, where N is shift value and ROT is from "ROTATE" because this is a cyclic shift.
For example, ROT2 means that "a" becomes "c", "b" becomes "d" and in the end "y" becomes "a" and "z" becomes "b". Number of possible transformations is dependent on alphabet length, and for english alphabet it is 25 (ROT0 and ROT26 do not change the input text). Due to this it is a very weak cipher, cause you can quickly check all possible combinations.
Calculator below outputs the table with all possible transformations. Non-alphabetic symbols like whitespaces and digits are not changed.