Laravel Validation rule for bitcoin adress

passes.php

   public function passes($attribute, $address)
    {

        $decoded = decodeBase58($address);
 
        $d1 = hash("sha256", substr($decoded,0,21), true);
        $d2 = hash("sha256", $d1, true);
 
        if(substr_compare($decoded, $d2, 21, 4)){
           return false;
        }
        return true;
}