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:  Data confidentially: 
1. Abstract of Cited Paper (BIB001):  Most recent Mobile ad hoc network (MANET) research has focused on providing routing services without considering security. The malicious node can easily disturb the functioning of routing protocols. Route discovery phase of Dynamic Source Routing (DSR) requires the ability to verify that no node has been deleted from the path, and no node can be inserted in the path without a valid authentication. In this paper, we present a security mechanism that provides message integrity, mutual authentication and two-hop authentication mechanism without the assistance of online certification authority. Our mechanism not only prevents identity impersonation, replay attacks, but also detect and drop inconsistent RREQ to save network bandwidth. 
2. Abstract of Cited Paper (BIB002):  Secure group communication with efficient self-organising key agreement protocol and small broadcast ciphertext is essential to many collaborative and distributed applications in mobile ad-hoc networks (MANETs). In this study, the authors propose a Chinese Remainder Theorem-based secure group communication scheme which is able to provide confidentiality service and non-repudiation service simultaneously. In the proposed scheme, all group members contribute their own public keys to negotiate a shared encryption public key, which corresponds to all different decryption keys. By using the shared public key and the respective secret key, confidentiality and non-repudiation can be obtained, respectively. Both are essential to secure group communication in MANETs. Compared with the exiting signcryption schemes for multiple recipients, the proposed self-organising scheme has much smaller ciphertext that does not increase with the size of the group. Accordingly, it is quite suitable to secure group communication in self-organising, distributed and resource-constrained MANETs.

Literature Review:
According to this service, each node or application must have access to specified services that it has the permission to access. Most of services that are provided by data confidentially use encryption methods but in MANET as there is no central management, key distribution faced lots of challenges and in some cases impossible. Authors in BIB001 proposed a new scheme for reliable data delivery to enhance the data confidentially. The basic idea is to transform a secret message into multiple shares by secret sharing schemes and then deliver the shares via multiple independent paths to the destination. Therefore, even if a small number of nodes that are used to relay the message shares, been compromised, the secret message as a whole is not compromised. Using multipath delivering causes the variation of delay in packet delivery for different packets. It also leads to out-of-order packet delivery. Integrity: According to integrity security service, just authorized nodes can create, edit or delete packets. As an example, Man-In-The-Middle attack is against this service. In this attack, the attacker captures all packets and then removes or modifies them. Authors in BIB002 presented a mechanism to modify the DSR routing protocol and gain to data integrity by securing the discovering phase of routing protocol. Non-Repudiation: By using this service, neither source nor destination can repudiate their behaviour or data. In other words, if a node receives a packet from node 2, and sends a reply, node 2 cannot repudiate the packet that it has been sent. Authors in BIB003 presented a new approach that is based on grouping and limiting hops in broadcast packets. All group members have a private key to ensure that another node couldn't create packets with its properties. But creating groups in MANET is challengeable. In previous part a brief discussion on security services and their challenges in MANET was provided. Detecting and eliminating malicious nodes, is another aspect of the MANET security. In the next section, important attacks in MANET and existing detection and/or elimination approaches to secure network against them is discussed.