On the Secure Dispersed Data TransferOriented Path Construction Method for Different ID Trees in WSNs In wireless sensor networks (hereinafter referred to as WSNs), sensor terminals (hereinafter referred to as nodes) have a possibility of being affected by attacks such as eavesdropping and node capture attacks because the nodes use the wireless multihop communication. To deal with this problem, secure dispersed data transfer using the secret sharing scheme has been proposed for WSNs having multiple gateways (hereinafter referred to as GWs). In this scheme, Source initiated Routing ID Routing (hereinafter referred to as SRIDR) is used to construct paths, and the number of control packets can be reduced. On the other hand, the routing ID, which is required for routing in SRIDR, may be exhausted in a large scale network, and multiple ID trees may be constructed. Therefore, it has drawbacks that some nodes belong to a different ID tree from the GWs and cannot construct paths to the GWs in a large scale network. In this paper, we propose a new method that enables nodes to construct paths to the GWs which belongs to a different ID tree. As a result of comparing our proposed method and the existing method through simulation experiments, we have confirmed that the path construction ratio was improved and the data packet delivery ratio was improved accordingly.

Joint Sybil Attack Prevention and Energy Conservation in Wireless Sensor Networks Sybil attacks, wherein a network is subverted by forging node identities, remains an open issue in wireless sensor networks (WSNs). This paper proposes a scheme, called Location and Communication ID (LCID) based detection, which employs residual energy, communication ID and location information of sensor nodes for Sybil attacks prevention. Moreover, LCID takes into account the resource constrained nature of WSNs and enhances energy conservation through hierarchical routing. Sybil nodes are purged before clusters formation to ensure that only legitimate nodes participate in clustering and data communication. CH selection is based on the average energy of the entire network to loadbalance energy consumption. LCID selects a CH if its residual energy is greater than the average network energy. Furthermore, the workload of CHs is equally distributed among sensor nodes. A CH once selected cannot be selected again for 1p rounds, where p is the CH selection probability. Simulation results demonstrate that, as compared to an eminent scheme, LCID has a higher Sybil attacks detection ratio, higher network lifetime, higher packet reception rate at the BS, lower energy consumption, and lower packet loss ratio.