## 2 Related Works
Moreover, the presented protocol needs not explicit information packets, but periodic information packets are needed. Its communication cost and storage cost which reach \(O(n)\) and \(O(n)\) respectively, are relatively reasonable. [PERSON] et al. [26] presented a method based on a polynomial based on the dispatches of key pairs. In the study, Bloom filters are utilized for verifiable authentication and collection of the total amount of key-pairs which is set up by each mobile node. If the total amount of pair-wise keys set up by the filters is more than the a predefined value, then the nodes are classified as replicas. However, this centralized protocol has a serious flaw. It guarantees nothing about whether the replicas report the right number of keys honestly. [PERSON] et al. [27] presented two decentralized approaches for clone detection in networks. Both of them are based on mobility-assistance. One approach is single storage of time-location claim and exchanges (UTLSE), the principle of the UTLSE protocol is that two nodes exchange related time-location information of the same monitored node until they meet with each other. Then one of the meeting witnesses is selected to detect the cloned node, and only one time-location claim is stored in the UTLSE protocol. Another scheme is called multi-time location storage and diffusion (MTLSD). The principle of MTLSD scheme is similar. The difference is that the second method stores more than one time-location for every monitored node and forwards the information among witnesses. As a result, a higher detection rate can be attained by the MTLSD scheme. In order to find captured nodes, in the study by [PERSON] et al. [28] two distributed approaches were presented which were called History Information exchange Protocol (HIP) and its optimized version (HOP). Both algorithms are based on the communication with its one-hop neighbor and the mobility. Meanwhile, two kinds of attack modes were defined and their behavior discussed. Their differences are listed as follows: the HIP will keenly observe and analyze node capture attacks only by the information local to the node, but the HOP needs to analyze node cooperation to detect node capture attacks. A study by [PERSON] et al. [29] depended on the neighborhood community, which can be characterized by the one-hop neighbor node list of the node to be detected. The rationale behind the scheme is that a node cannot appear in different neighborhood communities at any time. The first step of SHP is the fingerprint claim, where the neighbor node table is signed as the passport, and then the passport is broadcasted to one-hop neighbors. If the witnesses receive conflicting passports, there must be replicas present. [PERSON] et al. [30] presented a study for detecting replicas deployed in wireless sensor networks, whereby some moving nodes act as patrolmen to finish the detection. For static clone nodes, when patrollers migrate to a new region, they spread their patrol information and receive the location messages from surrounding static nodes, and then apply the security thesis that \"one benign node only has one location\" to detect replicas which have different locations with the same ID. In another interval, the patrollers move to another zone to repeat the same operation. If the clones have been present in a zone, the cloned nodes can be found out once the second conflicting location message is received. In other cases, the cloned node's answer messages are retrieved by different patrollers, and then they would be detected by the trusted third party or by exchanging information of patrol nodes after around. For the cloned patrol node, the basis of detection is that the speed of moving patrol node should never exceed the predefined maximum speed \(V_{\max}\). When the patroller broadcasts a patrol claim, there will be a static period interval of length T. Once the patroller broadcasts a patrol claim for a new location in time of [\(T\),\(T\) + _interval_], mobile cloned patrollers must exist.