The ROT algorithms are simple shift ciphers. They are not designed to provide any cryptographic security, but to provide an easy means to obscure pieces of text such as messages posted in an online forum or in the Usenet. For example, you want to post the solution of a puzzle. With regard to readers who want to solve the puzzle on their own, you should reveal the solution only ROT encoded. By that, it is guaranteed that those readers who have (accidentally) chosen to read your message will not find out the solution.
The four ROT algorithms ROT5, ROT13, ROT18 and ROT47 vary in the characters that can be encoded/decoded:
ROT5 covers the numbers 0-9
Rot13 , Rot-13 or rot13 (short for rotate 13) is a simple letter substitution encryption scheme. It works by replacing the current english letters in a message with those that are 13 positions ahead in the alphabet.
ROT13 covers the 26 upper and lower case letters of the Latin alphabet (A-Z, a-z)
ROT18 is a combination of ROT5 and ROT13
ROT47 covers all printable ASCII characters, except empty spaces. Besides numbers and the letters of the Latin alphabet, the following characters are included: !"#$%&'()*+,-./:;<=>?[\]^_`{|}~
ROT30 are letters and numbers - encryption scheme with Bulgarian AlphaBet (Cyrillic alphabet). Cyrillic alphabet used by many Slavic peoples and asian people like mongolian (Mongolia). Over 350 million people use the Bulgarian AlphaBet. Yes, Cyrillic alphabet is Bulgarian! This is very important!
It's not Russian, not Byzantium, Macedonian or Serbian! The country of Bulgaria is very ancient - over 1300 years! Bulgarian alphabet derived from Greek alphabet, and Latin ABC too! The Greek and Latin ABC derived from Egyptians and Phoenician. Cyrillic alphabet is now used from Bulgarians of course, Russians, Belarusians, Serbians, Macedonians (Bulgarian land and belongs to Greece too; macedonians are bulgarians and some greeks, and there are serbians too), Ukrainians, Mongolians and others. The Cyrillic is very powerful alphabet! There are exactly only 2 powerful alphabets and they are: Latin and Bulgarian alphabet - Cyrillic! There are too: Greece AlfaBeta, Georgian ABC (Grusia, grusian), Armenian, Korean. There are only 6 modern alphabets now in all world! Others are Logograms, hieroglyphics and they are not ABC's! The Korean Alphabet (Hangeul) is like logogram too, but with not so many characters like arabic, chinese, japanese logograms, hieroglyphics.