ROT13 community

ROT13 is a member of substitution cipher class. I had discuss two members of  this class, if you remember. 
          Atbash cipher
          Affine Cipher (shift cipher)

If you remember the history which I had share you. Atbash cipher encode message by shifting key = -1 but in inverse direction.
          A = Z, B = Y and so on.
However in shift cipher key = 3.

                Message : HELLO
                                : JGNNQ
Both ciphers are special affine cipher case.
As you know shift cipher had introduced by julius caesar in rome. Julius had encoded message by shifting letter 3 time forward, so that it will not understand. However after 2 or 3 decade later it's is easy to decipher. The above example use same technique.In Rot13 alphabets shift by 13 letters. 
           A = N, B = O and so on.
        

Let time to solve a riddle: 
                 Yrg cynl n tnzr. Zl anzr vf Ze K. Zngurzngvpf fbyir ernyvgl ceboyrzf, ohg fpvrapr yngre cebir gur inyvqvgl bs zngurzngvpf ehyrf. Pna lbh qrpvcure gur grkg 


Rot13 use in encoded email, window xp registry and many places. Later prove that this cipher is not enough power to protect confidential data. 

Rot is very large community. Rot1, Rot 2,.... Rot 26, Rot 47 are available .
Rot5 deal with numeric but there is limit 0 - 4 
Rot13 deal with uppercase letter have 26 limit
Rot18 deal with uppercase letters and numeric values.
In Rot47 numbers, uppercase letters, lowercase letters, punctuations are use to secure the message. Best of luck 
                              vFC 59GAI @63;2 D3< H9K47 3:C6 `b J?>= B3E7]
                               Sgzmj xnt Gzud z mhbd czx