# A Secure Protocol against Selfish and Pollution Attacker Misbehavior in Clustered WSNs
## 2 Related Work
A new refined scheme was proposed by [PERSON] and [PERSON] in [26] to remove this restriction but this type of scheme still needs computation of the hash values of each packet, thereby increasing the transmission delay and the required operations' complexity. [PERSON] et al. proposed an efficient homomorphic signature scheme based on the \(RSA\) signature [27]. In their scheme, the source signs its message using its private key. Intermediate nodes verify the received messages using the source's public key. The authors used a novel homomorphic function where the encoded message's signature is composed from those of the input messages (used to create the encoded message). Their scheme can accomplish source authentication and data verification. However, it increases transmission overhead, since the size of an \(RSA\) signature is typically very large. The authors of [28] proposed an identity-based digital signature scheme to detect pollution attacks in intra-session network coding. Their scheme does not involve a third-party query to certificate authority and does not have the key issue, and it does not take into consideration the energy consumption parameter in resource-constrained \(WS\)Ns. [PERSON] et al. [29] presented a privacy-preserving signature scheme for linear network coding-based networks. They used a homomorphic signature and applied new signing and verification processes that enhance the computational efficiency. Their scheme optimizes the inherent security potential of random network coding and provides countermeasures against both eavesdropping attacks and pollution attacks. By encrypting a message before signing it, the intermediate nodes are able to capture and discard fake packets. Although the homomorphic signature \(NC\) scheme can solve the problem of data integrity and confidentiality, the signature generation and verification processes remain high-energy expenses, reducing the transmission efficiency. Another approach, proposed in [30], used an identity-based linearly homomorphic signature scheme for \(NC\)-enabled wireless sensor networks to ensure data integrity and authenticity. In their scheme, the authors applied a signature generation and verification that are both independent of the size of the data packet to reduce the computation cost. They used the unique serial numbers of source nodes as an identity-based public key that is free of certificate management, allowing the destination to track the source of data. In the previous studies on solutions, whether for \(DoS\) attacks or pollution attacks, we noted several disadvantages. In the solutions tackling \(DoS\) attacks, some ignored the case where the \(CH\)s are the malicious nodes in the network, despite their major role in controlling data routing, which can affect network availability. Others focused only on solutions for detecting \(DoS\) attacks and not for preventing them. Others approaches used cryptographic mechanisms with high computational costs. Solutions attempting to resist pollution attacks, using hash functions or homomorphic signatures, are computationally expensive and may lead to traffic overhead. Our solution tackles both \(DoS\) and pollution attacks, along with eavesdropping attacks. In contrast to the previous work concerning network availability, the solution proposes a prevention as well as a detection scheme for misbehaving \(CH\) nodes. It ensures original packets reach their destination even if a number of packets are dropped. In addition, it considers the case where the \(CH\) nodes are malicious. Moreover, our solution takes advantage of the \(NC\) technique used in [15] to guarantee data confidentiality and optimizes it by achieving data coding only at source nodes. Hence, it minimizes overheads and energy depletion in the network.