The increasing popularity of Android devices gives birth to a large amount of feature-rich applications (or apps) in various Android markets. Since adversaries can easily repackage malicious code into benign apps and spread them, it is urgent to detect the repackaged apps to maintain healthy Android markets. In this paper we propose an efficient detection scheme based on twice context triggered piecewise hash (T-CTPH), in which CTPH process is called twice so as to generate two fingerprints for each app to detect the repackaged Android applications. We also optimize the similarity calculation algorithm to improve the matching efficiency. Experimental results show that there are about 5% repackaged apps in pre-collected 6438 samples of 4 different types. The proposed scheme improves the detection accuracy of the repackaged apps and has positive and practical significance for the ecological system of the Android markets.

With the increasing popularity and rising demand for high - rate wireless Internet access , traditional wireless access networks such as cellular network and Wireless Local Area Network (WLAN) are facing some challenges . The Wireless Mesh Network (WMN) is emerging as a flexible and low- cost alternative to provide multi- hop communications , supporting applications such as last- mile Internet delivery. The WMN has also become a promising technology in the merging of wireless networks . Some key technologies for the WMN networking , including network configuration , power control, mobility management, access control, and routing protocols , are analyzed ; the routing protocol design in WMN and mobile Ad hoc network are compared . An example of WMN testbed based on WLAN and second - layer switching technology is given .