- substr: documentation ( source)
- strpos: documentation ( source)
- str_repeat: documentation ( source)
- explode: documentation ( source)
<?php
$charset=str_repeat("abcdefghijklmnopqrstuvwxyz",2);
$msg="tm bcsv qolfp f'dmvd xuhm exl tgak hlrkiv sydg hxm qiswzzwf qrf oqdueqe dpae resd wndo liva bu vgtokx sjzk hmb rqch fqwbg fmmft seront sntsdr pmsecq";
$format=explode(" ",$msg);
for($element=0;$element<=count($format);$element++){
$string=$format[$element];
$len=strlen($string);
$key=$element+1;
print $string." ".$len." ".$key."\n";
for($char=0;$char<=$len-1;$char++){
$l=strpos($charset,substr($string,$char,1));
print substr($string,$char,1)."\n";
$n=substr($charset,$l+$key,1);
print $n."\n";
}
}