Password description of ROT 13

To apply ROT 13 to a paragraph of text, just check the alphabetical order of characters and replace the corresponding letters after 13, and wrap around the beginning of 26 English letters if necessary [2]. A is replaced by N, B is replaced by O, and so on until M is replaced by Z, and then the order is reversed: N is replaced by A, O is replaced by B, and finally Z is replaced by M. Only these characters appearing in English letters are affected; Numbers, symbols, spaces and all other characters remain unchanged. Because there are only 26 English alphabets and 26=2× 13, the ROT 13 function is its own inverse function:

For any character x: rot13 (rot13 (x)) = rot26 (x) = x.

In other words, two consecutive ROT 13 application functions will restore the original text (mathematically, this is sometimes called involution; In cryptography, this is called reciprocal.

The conversion can be completed by using a look-up table, as shown in the following example: abcdefghijklmnopqrstuxyzabcdefghijklm nopqrstuxyzabcdefghijklm For example, the essence of the following English joke is hidden by ROT 13: How to distinguish an extrovert from an Ann?

Introverted in NSA? Va gur ryringbef，

gurkgebireg ybbxf ng gurbgurethl ' f fubrf。 The full text was transformed by ROT 13, and the answers to the jokes were revealed as follows: Ubj pna lbh gryy na rkgebireg sebz na.

Wandering AFN In the elevator,

Look at each other's shoes extremely. The second ROT 13 function will turn back to the original text.