# FarpScun: Fully Anonymous Routing Protocol with Self-Healing Capability in Unstable Sensor Networks
###### Abstract  
Anonymous technology is an effective way for protecting users' privacy. Anonymity in sensor networks is to prevent the unauthorized third party from revealing the identities of the communication parties. While, in unstable wireless sensor networks, frequent topology changes often lead to route-failure in anonymous communication. To deal with the problems of anonymous route-failure in unstable sensor networks, in this paper we propose a fully anonymous routing protocol with self-healing capability in unstable sensor networks by constructing a new key agreement scheme and proposing an anonymous identity scheme. The proposed protocol maintains full anonymity of sensor nodes with the self-healing capability of anonymous routes. The results from the performance analysis show that the proposed self-healing anonymity-focused protocol achieves full anonymity of source nodes, destination nodes, and communication association. wireless sensor network; anonymous routing protocol; diffie-hellman key exchange algorithm; anonymous identification scheme; self-healing capability  
based on onion routing [8]. In 2019, [PERSON] et al. proposed an anonymous routing scheme to protect location privacy in wireless sensor networks by setting a proxy source node and setting a branch area around the base station [9]. Self-healing anonymous routing achieves self-healing on the basis of anonymous routing. In many cases, wireless sensor networks are unstable, and their topologies may change over time. In 2019, [PERSON] et al. proposed the self-healing concept in routing protocols. We call a routing algorithm \"self-healing\" if it satisfies the following two conditions:  
1. After the local network topology changes, the route can be modified locally and dynamically, and finally the route is optimized and the total energy consumption is saved. 2. When the network topology changes, it is not necessary to reinitiate the routing request and route reply, which greatly improves the system efficiency [10]. Self-healing can ensure that routes can effectively adapt to the changes of the network topology on the unstable sensor networks. In 2009, [PERSON] et al. proposed a multi-next hop self-healing routing technology that is based on loop avoidance and local fast self-healing methods e.g., [11]. In 2015, in order to solve the problems of severe routing flooding and poor self-healing performance of existing wireless network routing algorithms, [PERSON] et al. proposed a centralized self-healing routing algorithm by introducing the idea of centralized routing and multi-route strategy into self-healing routing [12]. In 2019, [PERSON] et al. proposed a lightweight decentralized adaptive anonymous routing scheme by combining onion routing for the initial global route request and threshold-based secret sharing for the subsequent local route tuning/healing [10]. Most of the existing self-healing anonymous communication protocols in wireless sensor networks cannot provide source node anonymity, destination nodes anonymity, and communication association anonymity at the same time. The attacker can track the source node or the base station according to the identity field in the message. If the identity or location of the source node or the destination node is leaking, then it may cause large damage to the deployed sensor networks [13]. Therefore, it is very important to maintain the anonymity of nodes during data communication [14]. This paper proposes an enhanced anonymous routing protocol with self-healing capability in unstable sensor networks in order to solve the problem of route-failure and weak anonymity in the existing self-healing anonymous routing protocol.The key contributions of this paper are listed, as follows. 1. A new anonymous identities scheme is proposed. It includes three parts. * A novel key distribution and sharing scheme is proposed to provide keys for the following anonymous identity generation and updating process. * A new anonymous identity generation scheme is proposed to protect the identity privacy of the sensor nodes.