Study On Security Mechanism In AD Hoc Network For Emergency Communications

Emergency communications may be faced with the difficulties that the time, place, and scale is difficult to predict, and when disaster events occur, the existing communication facilities are damaged, while mobile ad hoc network is a distributed wireless network, it does not rely on a pre-existing infrastructure and is becoming an important means for emergency communications. While, mobile ad hoc networks are more vulnerable to various attacks and more frangible in security, because it has features such as open media, dynamic topology, distributed collaboration, capacity-constrained and so on. The key questions of security in mobile ad hoc networks are authentication of users. Therefore, it is very important to study ad hoc network authentication mechanism for emergency communications.This paper introduces ad hoc network technology, analyze its characteristics, security threats and security objectives at first, and then Cryptography and authentication technologies, highlighting the secret sharing scheme based on threshold cryptography, after that discusses characteristics of several typical certification mechanism. On the basis of distributed authentication mechanism, this paper presents a cluster based distributed authentication scheme that fits for emergency communications. This scheme uses trust decentralized strategy and divides CA’s function into several nodes. These nodes cooperate together to perform CA’s function. When the new node requests a certificate, it needs to apply to at least threshold values of service nodes. When it collects threshold values of part of certificate issued by the service node, it can use certificate synthesis algorithm to get a complete certificate. So, this scheme solves certificate signature issues in ad hoc network for emergency communications and failure problem of a single point in centralized authentication scheme. When cluster head requests to join ad hoc emergency communications network, applies for a certificate, we use partly distributed authentication scheme; when the ordinary node requests to join the cluster, applies for a certificate, we use fully distributed authentication scheme. Also, we take Feldman verifiable secret sharing scheme to solve untrusted participants or distributor in the secret sharing process, and use inspection legitimacy of partly certificate to check whether the certificate is legal to solve the problem of illegal certificates issued by the malicious nodes. At last, we analyze this scheme from its security and simulation results, showing this scheme has a high security and authentication performance, so that it fits for authentication process in ad hoc network for emergency communications.