Caeser encryption algorithm in PHP -

is there way use caeser encryption string in php; have come .net not know much.

take example:

original aaaaaa after ceaser encryption bbbbbb 

next example:

original abcd after ceaser encryption bcde 

could make function out of echo $output;

here's 1 version works ascii letters:

function caesar($str, $shift) {     $len = strlen($str);     $ord_alpha_upper = ord('a');     $ord_alpha_lower = ord('a');     $shift = $shift % 26 + 26; // takes care of negative shifts     for($i = 0; $i < $len; ++$i) {         $chr = $str[$i];         if (ctype_upper($chr)) {             $str[$i] = chr($ord_alpha_upper + (ord($chr) - $ord_alpha_upper + $shift) % 26);          }         else if (ctype_lower($chr)) {             $str[$i] = chr($ord_alpha_lower + (ord($chr) - $ord_alpha_lower + $shift) % 26);         }     }      return $str; } 

you can use both positive , negative shifts , work correctly no matter shift distance.

however, aware php has no concept of character encoding (strings byte arrays), if input not in single-byte encoding or utf-8 not work correctly.