You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Security challenges in mobile ad hoc networks:a survey 
Chapter Title:  FUTURE DIRECTIONS OF RESEARCHES 
1. Abstract of Cited Paper (BIB001):  Mobile ad hoc network is a dynamic wireless network of mobile nodes without any centralized control. Energy efficient routing is the most challenging task of MANET. Clustering in MANET gives energy efficient solution. In this paper we proposed a secure clustering algorithm using multi-objective particle swarm optimization technique. The algorithm uses three objective functions based on nodes QoS parameters: trust value, life time and available bandwidth. The main advantage of MOPSO is that it provides multiple solutions at a time through optimal Pareto front. The proposed approach is simulated with MATLAB and NS2. Here we have discussed the performance of the proposed approach by varying number of nodes and transmission range of nodes.

Literature Review:
Until now we briefly discussed the security challenges in MANET and present some analytics in them. In this section we present open research issues. Routing information approaches are suitable in all types of MANET. In this approach, reducing packet overhead and processing time, beside increasing accuracy is an important challenge. By increasing accuracy, it can detect cooperative malicious nodes. With decreasing processing time of this approach MANETs flexibility will increase. Sniffing approach is useful in the case of single attacks, as it is unable to detect cooperative nodes. Whoever, it waste nodes energy and it is not suitable in MANET with high speed nodes. Finding a more effective way to calculate the threshold and present effective detection mechanism forasmuch as decreasing time and packet overhead is the open border of research in sniffing approaches. Beside it, detecting cooperative malicious nodes is challengeable. In order to solve this challenge comparing sniffing with other defeating approaches is recommended. MANET is self-organized, self-configurable network without any centralized control. Therefore, encryption and authentication are challengeable. Key distribution and control unit are the most important challenges. One way to over through these challenges is using clustering; therefore, the Cluster Head can act as the key distributer. Because of MANETs dynamic topology, creating and maintain clusters is highly challengeable. Using fuzzy logic BIB001 or swarm based BIB002 is highly recommended for this challenge. As another research interest, decreasing processing time and processing overhead of encryption approach can be mentioned. Redundancy approaches, generate lots of duplicated packets and waste nodes resources. Also it increases congestion and packet lost. Effectively choosing number of duplicated paths, based on risk level, is highly challengeable. Also combining this approach with some other approaches in order to detect malicious nodes is another challengeable issue. Dynamic frequency is effective in multi-type MANETs. By using this approach in multi-type MANET, each node secures its packets by sending in different frequencies. In addition, breaking one frequency has no effect on others. This is a challenge in this approach.