This function generates a invite_code against a user email.


// Token generation example
function calculate_seed_value($email, $constant_value) {
    $email_length = strlen($email);
    $email_hex = hexdec(substr($email, 0, 8));
    $seed_value = hexdec($email_length + $constant_value + $email_hex);

    return $seed_value;
}
     $seed_value = calculate_seed_value($email, $constant_value);
     mt_srand($seed_value);
     $random = mt_rand();
     $invite_code = base64_encode($random);