php - How to generate same random string from two numbers even if we swap them? -

i looking following logic in php:

1. first number 491
2. second number 784

goal generate common encrypted string these 2 numbers, if reverse them:

    <?php                           function common_string_generator($num1, $num2) {                   return enc_string_generator($num1, $num2);           }           # first            $room_one = common_string_generator(491, 784);            # second           $room_two = common_string_generator(784, 491);           if($room_one===$room_two) {                 print "success";           } else {                 print "failure";           }     ?>      #am here:      <?php              ........             $n1 = md5($num1, $num2);             $n2 = md5(num2, num1);             ........     ?> 

3. i not able fix order of both numbers got reverse since both numbers ids of users going private chat room.

4. the both ids unique, , encrypted string these unique, want unique encrypted string become id of chat room.

you arbitrarily decide use smaller number first parameter , larger 1 second:

function common_string_generator($num1, $num2) {     $param1 = min($num1, num2);     $param2 = max($num1, num2);     return enc_string_generator($param1, $param2); }