“…However, because of broadcast nature of wireless communication, dynamic topology, mobility, signal channel instability, and so forth [1], they are also vulnerable to various security threats and attacks such as DoS (Denial of Service), counterfeiting, tampering, leakage, interference, network flooding, eavesdropping, and traffic analysis [2]. Particularly, with the popularity of intelligent terminals, some bad information, such as obscenity information, viruses, and Trojans, becomes more and more widespread [3]. This bad information not only occupies lots of user's traffic, but also endangers the privacy of users.…”