PHP Mask a String
Quick function for masking an account number, credit card number, or whatever else.
function mask ( $str, $start = 0, $length = null ) { $mask = preg_replace ( "/\S/", "*", $str ); if( is_null ( $length )) { $mask = substr ( $mask, $start ); $str = substr_replace ( $str, $mask, $start ); }else{ $mask = substr ( $mask, $start, $length ); $str = substr_replace ( $str, $mask, $start, $length ); } return $str; } // Usage: $string = '1234 5678 9123 45678'; echo mask($string,null,strlen($string)-4); // *************5678