<?php
function Cipher($ch, $key)
{
if (!ctype_alpha($ch))
return $ch;
$offset = ord(ctype_upper($ch) ? 'A' : 'a');
return chr(fmod(((ord($ch) + $key) - $offset), 26) + $offset);
}
function Encipher($input, $key)
{
$output = "";
$inputArr = str_split($input);
foreach ($inputArr as $ch)
$output .= Cipher($ch, $key);
return $output;
}
function Decipher($input, $key)
{
return Encipher($input, 26 - $key);
}
$text = "rifqi";
$cipherText = Encipher($text, 3);
$plainText = Decipher($cipherText, 3);
echo $cipherText."\n";
echo $plainText;
?>
