Secure communication of the location information or localization of sensor nodes in an adversarial environment is a high priority yet a challenging task. Wireless sensor networks are characterized by severe constraints such as memory, energy, processing and operational environment. Unlike other wireless networks, a sensor network has to be highly sensitive to energy consumption. Complexity and power consumption of sensor nodes must be as low as possible. A light-weight and secure localization mechanism is needed to optimize the WSN performance from a security perspective. In this paper we present a two-way ldquoGreet, Meet and Locaterdquo mechanism for secure location estimation in large scale wireless sensor networks based on geographical sectorization. A double-averaging mechanism is also presented that uses a time of arrival (TOA) based localization technique to help minimize the location estimation errors.