Security challenges in mobile ad hoc networks:a survey <s> Cluster-based Security: <s> Mobile Ad Hoc Networks (MANETs), due to their lack of physical infrastructures or centralized online authorities, pose a number of security challenges. Traditional network authentication solutions rely on centralized trusted third party servers or certificate authorities. However, ad hoc networks are infrastructure-less, and there is no centralized server for key establishment. Hence, traditional solutions do not meet the requirements of MANETs. In this paper, a key establishment protocol for mobile ad hoc networks is proposed which does not require any centralized support. The mechanism is built using the well-known technique of threshold secret sharing scheme and network clustering. This protocol is robust and secure against a collusion of up to a certain number of nodes and is well adapted with node movements. Due to use of clustering, the imposed overhead is very low compared with other similar key establishment protocols. <s> BIB001 </s> Security challenges in mobile ad hoc networks:a survey <s> Cluster-based Security: <s> The migration from wired network to wireless network has been a global trend in the past few decades. The mobility and scalability brought by wireless network made it possible in many applications. Among all the contemporary wireless networks, Mobile Ad hoc Network (MANET) is one of the most important and unique applications. MANET is a collection of autonomous nodes or terminals which communicate with each other by forming a multi-hop radio network and maintaining connectivity in a decentralized manner. Due to the nature of unreliable wireless medium data transfer is a major problem in MANET and it lacks security and reliability of data. A Key management is vital part of security. This issue is even bigger in wireless network compared to wired network. The distribution of keys in an authenticated manner is a difficult task in MANET and when a member leaves or joins it need to generate a new key to maintain forward and backward secrecy. In this paper, we propose a Clustering based Group Key Management scheme (CGK) that is a simple, efficient and scalable Group Key management for MANETs and different other schemes are classified. Group members compute the group key in a distributed manner. <s> BIB002
These approaches use clustering in order to provide more efficient situations for security protocols. Generally in these approaches, clusters are used for key distribution or as central management for controlling other nodes. Using clustering for security goals is important as it could solve problems in key distribution or key management. Authors in BIB002 BIB001 provides a key distribution mechanism by using clusters. Clustering can solve some of security challenges but cluster creation and maintenance is highly challengeable due to MANET's dynamic topology. In incorporating approaches based on application, one challenge may be more important than the other one. For example, when selecting best path in routing is not as important as security, an approach can choose more secure paths without emphasizing on best routing path. As an example, in AODV routing protocol, the path with low sequence number is chosen as the best path. The reason is that, if there be a malicious node, it will send high sequence number. Using these benefits of incorporating approaches, both challenges will be solved with better security parameters.