ROT-47 Cipher

The Rot-47 is a shift cipher that allows to encode all visible ASCII characters (where Rot13 cipher can only encode letters).

Rot47 uses a 94-character alphabet that is a subset of the ASCII table characters between the character 33 ! and the character 126 ~.

Rot47 encryption consists in replacing a character with another located 47 positions after in the alphabet. The conversion table to shift is:
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO
PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~

The decryption of the Rot-47 is identical to the encryption because the substitution alphabet used is reversible.
PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO

The ASCII code defines 94 printable characters, so a rotation of half (94/2 = 47) makes it possible to obtain a symmetric cipher, similar to ROT13 (for the 26 letters of the alphabet).

The message uses ASCII characters and contains common letters as 6 or t which are the ciphered values of E and e.

Rot47 is a simple way to encode a message on discussion forums or social networks.

Rot-47 is a variant of Rot13, itself a variant of the Caesar cipher, a special case of shift cipher.

An implementation of ROT47 could be:

// Pseudo-code
function rot47(string) {
foreach (char in string) {
code = ascii_code(char)
if (32 < code < 80) char = ascii_char(code + 47)
if (79 < code < 127) char = ascii_char(code - 47)
}
return string
}


// Javascript
function rot47(x){
var s='';
for(var i=0;i<x.length;i++){
var j=x.charCodeAt(i);
if((j>=33)&&(j<=126)){
s+=String.fromCharCode(33+((j+14)%94));
}
else {
s+=String.fromCharCode(j);
}
}
return s;
}