# An Untraceable Data Sharing Scheme in Wireless Sensor Networks
###### Abstract  
With the wide application of wireless sensor networks (WSNs), secure data sharing in networks is becoming a hot research topic and attracting more and more attention. A huge challenge is securely transmitting the data from the source node to the sink node. Except for eavesdropping the information stored in the packages, the adversary may also attempt to analyze the contextual information of the network to locate the source node. In this paper, we proposed a secure data sharing approach to defend against the adversary. Specifically, we first design a secret key mechanism to guarantee the security of package delivery between a pair of nodes. Then, a light-weighted secret sharing scheme is designed to map the original message to a set of shares. Finally, the shares are delivered to the sink node independently based on a proper random routing algorithm. Simulation results illustrate that our approach can defend against the eavesdropping and tracing-back attack in an energy-efficient manner. untraceable; wireless sensor networks; security; data sharing +
Footnote †: journal:  
0000-000-0000-0000-0000-0000-0000-0000-0000-0000-0000-00000-0000-0000-0000-00000-00000-00000-00000-00000-00000-00000-00000-00000-00000-000000-000000-00  
actions. However, this is unrealistic for a large network considering economic factors. Moreover, if the adversary can indeed monitor the whole network thoroughly, we can infer that he can directly monitor the target in this area and need not locate the target by analyzing the network traffic. A more practical adversary model is the local adversary model [4; 5; 8; 9; 10; 11]. In this model, the adversary can monitor a local area with a similar size to that of a sensor node's communication area and knows all the radio actions in this area. In this model, the adversary finds the source node by tracing back hop-by-hop. Roughly speaking, the adversary starts from the sink node and if he finds that node \(A\) sends a message, he moves to node \(A\) and continues to monitor the surrounding environment. If the adversary finds that node \(B\) sends a message, he moves to node \(B\). By iterating the above process, the adversary can finally find the source node. The detailed trace back attack in this paper will be given in Section 4. To defend against the local adversary, routing-based source-location privacy protection schemes [9; 10; 11] are proposed. In these schemes, the source node does not directly send the message to the sink node. The source node first sends the message to a random agent node and then the message is transferred by the agent node to the sink node. In this way, the routing paths are diversified, and it is difficult for the adversary to receive a continuous flow of the packages to find the source node. However, if the sensing range of the adversary is large or the target stays in a location for a long time, it is highly possible that the adversary can find the target [8]. To further improve the security of the source node, in this paper, we mainly focus on a novel attack named hot-spot attack [4] and propose an untraceable data sharing scheme in WSNs. In the proposed scheme, we designed a secret sharing scheme based on the congruence equations and it can map the original message to a set of shares that are much shorter in length. Based on the shares, a cloud is constructed around the source node in which all the sensor nodes are indistinguishable in statistics. Theoretical analysis and simulation show that our cloud is much more energy-efficient than that of existing schemes. On the border of the cloud, the shares are independently transmitted to the sink node by a proper random routing algorithm. Finally, the sink node recovers the original message from the received shares and then the data delivery process from the source node to the sink node is completed. Simulation results illustrate that our scheme can strongly protect the location of the source node in an energy efficient way.