create a random string in php

function generateRandomString($length = 25) {
    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $charactersLength = strlen($characters);
    $randomString = '';
    for ($i = 0; $i < $length; $i++) {
        $randomString .= $characters[rand(0, $charactersLength - 1)];
    }
    return $randomString;
}
//usage 
$myRandomString = generateRandomString(5);function rand_str() {
    $characters = '0123456789-=+{}[]:;@#~.?/&gt;,&lt;|\!"£$%^&amp;*()abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $randomstr = '';
    for ($i = 0; $i < random_int(50, 100); $i++) {
      $randomstr .= $characters[rand(0, strlen($characters) - 1)];
    }
    return $randomstr;
  }