Pair-wise key establishment with authentication is basic and necessary to configure secure sensor networks. In addition, nodes in a sensor network may be lost because of the power exhaustion problem or malicious attacks. Thereby pair-wise key establishment and new node deployment are necessary in the sensor network. Recently, a study was proposed a practical access control protocol for Secure Sensor Networks based on the elliptic curve cryptography. We point out its weakness and propose more efficient scheme as satisfying better security strength.