Wireless networks need more security in comparison to the other networks due to their intrinsic vulnerabilities to possible attacks. It is expected that by using a distributed method for true random number generators (TRNG) in wireless sensor networks (WSN) and wireless LAN (WLAN) randomness quality of generated numbers can be enhanced. We analyze a protocol for a distributed TRNG named ScatterLight (L.R. Giuseppe, M. Fabrizio and O. Marco, 2011) for a WSN. After making some changes on ScatterLight structure and physical data sources, the Enhanced ScatterLight protocol is introduced; it provides secure and high qualified true random numbers. Thus, the quality of randomness of obtained random numbers using National Institute of Standards and Technology tests is evaluated. Finally, by analyzing the results, it can be conducted that Enhanced ScatterLight protocol in comparisons with ScatterLight protocol in WLAN and LAN provides 60% and 53% better randomness quality respectively, while the performance is equal in both protocols.

During last decade, wireless ad hoc networks have been widely used for communication, transferring data or sharing some information for specific members.Nowadays security protocols play a fundamental role to provide a level of security for wireless local area networks (WLAN). Moreover, one of the most important issues to improve security by help of cryptography algorithms is generating a common key among participants to intercommunicate securely. The aim of thesis is creating a common secret key by means of Diffie Hellman (DH) technique, so the contributory group key exchange protocol is established in order to perform efficiently in context of ad hoc. To this aim, some analysis on Biswas's protocol (G. done. Tseng's protocol fails to establish a common key in some situations, when the key generated by DH technique is not invertible. Thus, it is modified in order to fix the problem and achieve better performance in view of the computational cost for the proposed Tseng's modified protocol. Furthermore, theoretical analysis shows that computational cost in Tseng's modified protocol for each participant and the controller is decreased about 1.5 and 3 times in comparison with Tseng's protocol respectively. Tseng modified protocol is implemented and is tested for ad hoc WLAN with 3, 4, and 5 nodes.

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