The paper presents a new security solution in ubiquitous computing, which is a new and hot research point for computer scientists. Ubiquitous computing environments with their interconnected devices and services promise seamless integration of digital infrastructure into our daily lives. While the focus of current research is on how to connect new devices and build useful applications to improve functionality, the security and privacy issues in such environments have not been deployed widely to justify the evidence of threats, risk and vulnerability in real situations. Existing policies and mechanisms may not provide adequate guarantees to deal with new exposures and vulnerabilities introduced by the ubiquitous computing paradigm. In this paper we explore the challenges for building security and privacy into ubiquitous computing, describe our prototype implementation based on neural cryptography, and propose some directions for future work in the end.