About Enkripsi ROT-n

ROT-n (rotate by n) is a simple encryption algorithm uses a shift n alphabets to convert plain text into cipher text. This means that if the ROT-13, the alphabet A is replaced with N whereas the alphabet B is replaced by O and so on.

By following simple algorithm using ROT-13:
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm

From the picture above clearly shows that the ROT-13 every alphabet A will be replaced with the alphabet N, each alphabet A will be replaced with n alphabet. And so on.

example:
COMPUTER (plain text)
XBZCHGRE (cipher text, ROT-13 encryption results)
BfDGLKvI (cipher text, ROT-17 encryption results)
 This algorithm repeatedly stated by Julius Caesar to communicate with his commanders.

Application ROT-n in PHP

Quoted from http://php.net/manual/en/function.str-rot13.php ROT-13 can be directly used in the name of the function str_rot13.
Here's an example of its use:

string str_rot13 ( string $str )

Performs the ROT13 encoding on the str argument and returns the resulting string.

The ROT13 encoding simply shifts every letter by 13 places in the alphabet while leaving non-alpha characters untouched. Encoding and decoding are done by the same function, passing an encoded string as argument will return the original version.

 

<?php echo str_rot13('PHP 4.3.0'); // CUC 4.3.0 ?> 

However, we can actually create their own function to ROT-n in PHP. Here's an example of application:

/ * ROT-13, save the file name rot13.php * /

<p>Enter the text to be converted to / from ROT-13</p>
 <form action="rot13.php" method="get">
 <input type="text" name=string>
 <input type="submit">
 </form>
 <?php

function rot13($s) {return !$s?"":strtr($s,"NnOoPpQqRrSsTtUuVvWwXxYyZzAaBbCcDdEeFfGgHhIiJjKkLlMm",
"AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz");}

if (isset($_GET['string']))
         {
         $string = $_GET['string'];
         $rot = rot13($string);
              echo "Conversion result is <b>$rot</b>";

          }
 ?>

/ * ROT-17, save the file name rot17.php * /

<p>Enter the text to be converted to / from ROT-17</p>
 <form action="rot17.php" method="get">
 <input type="text" name=string>
 <input type="submit" name="submit" id="submit" value="Konversi">
 </form>
 <?php

function rot17($s) {return !$s?"":strtr($s,"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
"RSTUVWXYZABCDEFGHIJKLMNOPQrstuvwxyzabcdefghijklmnopq");}

if (isset($_GET['string']))
         {
         $string = $_GET['string'];
         $rot = rot17($string);
              echo "Conversion result is <b>$rot</b>";
         }
 ?>

So, good luck

Recent Posts