ROT13 is an encryption cipher belonging to a class called Caesar Ciphers in which each letter in the source message is exchanged with the letter X number of letters away in the alphabet. It has become a technical shorthand for using the Caesar Cipher with a distance of 13. For instance:
source: “A man, a plan, a canal: Panama!”
ROT13: “N zna, n cyna, n pnany: Cnanzn!”
source: “The quick brown fox jumped over the lazy dogs.”
ROT13: “Gur dhvpx oebja sbk whzcrq bire gur ynml qbtf.”
ROT13 came into moderate use during the height of Usenet as a way to obscure profanity, dirty talk, movie spoilers, open secrets, anything the message poster wants to say with a cupped mouth out of kindness to the other readers. Due to its popularity, some Usenet client software had ROT13 capabilities built-in as a convenience to the user. It is easily breakable, as are all of the Caesar ciphers, because the letter frequencies in the message are maintained, e.g. since “E” is the most common letter used in English writing, then any Caesar ciphertext that has “H” as the most common letter likely has a distance of 3, and the message can be decrypted. The capitalization, punctuation, and numbers are unencrypted.
A few months ago, I went to Slashdot to check the day’s tech news. They have a fortune cookie at the bottom of their page that changes daily. It’s usually some sharp quip or a random joke. This one day, it was a long, long string of garbage text that went on for pages. I saved the text for analysis later, and looked at it this morning. Here is a sample of the text:
Continue reading “This Will ROT13 Your Brain”
