Today's security systems have been drawing great attentions as cryptographic algorithms have gained popularity due to the nature that make them suitable for use in constrained environment such as mobile sensor information applications, where computing resources and power availability are limited. Elliptic curve cryptography (ECC) is one of them, which requires less computational power, communication bandwidth, and memory in comparison with other cryptosystem. In particularly, in order to save pre-computing there is a trend for sensor networks to design a sensor-group-leader rather than every sensor node communicates to the end database, which indicated the needs to prevent from the man-in-the middle attacking. In this paper we first present an algorithm that we called “hidden generation point” ECC protocol to protecting the ECC key exchange system from the man-in-middle attacking in wireless sensor networks. Even though there are other ways to be investigated, which will published in other paper, the major contribution in this paper is showing the hidden generation point” works. Also it is noted that the agent technology provides a method for handling increasing software complexity and supporting rapid and accurate decision making. A multi-agent applying for key exchange is motioned even the further discussed will be presented in another paper as the major task of this paper is presenting “hidden generation point”.