The existing privacy preservation methods in location-based services only focus on the protection of user location and identification information. It produces the truth of sensitive homogeneity attack when the queries in a cloaking set are sensitive information. To solve this problem, a personalized (k,p)-sensitive anonymization model was presented. On the basis of this model, a pruning tree-based cloaking algorithm called PTreeCA was proposed. The tree-type index in the spatial database has two features. The one is that mobile users are roughly partitioned into different groups according to the locations of mobile users; the other one is that the aggregated information can be stored in the intermediate nodes. By utilizing the two features, PTreeCA could find the cloaking set from the leaf node where the query user is and its sibling nodes, which are benefit for improving efficiency of the anonymization algorithm. The efficiency and effectiveness of PTreeCA are validated by a series of designed experiments on the simulated and real data sets. The average success rate is 100%, and the average cloaking time is only about 4ms. The experimental results show that PTreeCA is effective in terms of success rate, cloaking time, and the anonymization cost when the privacy requirements levels are low or medium.
To solve high energy and time delay cost problems caused by wormhole detection in Ad Hoc networks, a light-weighted wormhole detection method, using less time delay and energy, was proposed. The method used the neighbor number of routing nodes to get a set of abnormal nodes and then detect the presence of a wormhole by using the neighbor information of abnormal node when routing process was completed. The simulation results show that the proposed method can detect wormhole with less number of routing query. Compared with the DeWorm (Detect Wormhole) method and the E2SIW (Energy Efficient Scheme Immune to Wormhole attacks) method, it effectively reduces the time delay cost and energy cost.