Pervasive computing is an environment where there is a strong integration between networked computing devices from small sensors to very large and powerful devices with human and their ambient environments. To achieve "anytime, anywhere" computing without requiring users, there is a need for essential element. Privacy and security issues, however, have not been properly addressed. Hence there is no security for personal data and devices and network services may be inconvenient to use.
In another angle, we can define Pervasive computing as a technology that pervades the users' environment by making use of multiple independent information devices interconnected seamlessly through wireless or wired computer communication networks which are aimed to provide a class of computing/sensory/communication services to a class .