private function pemInitialDataCheck($keypair)
    {
        if (true === empty($keypair) || false === is_array($keypair) || strlen($keypair[0]) < 62 || strlen($keypair[1]) < 126) {
            throw new \Exception('Invalid or corrupt secp256k1 keypair provided.  Cannot encode the keys to PEM format.  Value checked was "' . var_export($keypair, true) . '".');
        }
    }