Description: ------------ There are two things wrong with str_shuffle: 1) It shouldn't seed mt_srand. For PHP < 4.2, people should be seeding the random number generators in the main program, and for PHP > 4.2, it's unnecessary (actually bad on a fast machine because it may reseed within the same microsecond). 2) Appending to the result string ($new) causes quadratic behavior. Either append to an array and implode() it on return, or create a string and swap characters inside it. Here's code that swaps characters (drop-in replacement for the function's body). Warning: Untested. $result = (string) $str; for ($i = strlen ($str) - 1; $i >= 0; $i--) { // Swap random character from [0..$i] to position [$i]. $j = mt_rand (0, $i); $tmp = $str [$i]; $str [$i] = $str [$j]; $str [$j] = $tmp; } return $result;

Hope you fixed my mistake. (The loop should be reading and updating $result instead of $str.)