近年來，隨著行動隨意網路的快速發展與演變，汽車隨意網路(Vehicular ad hoc networks)已成為行動隨意網路中最具吸引力的應用之一。然而，由於汽車隨意網路中，節點自我集結與高速移動的特性，以及非集中式的網路拓樸架構，在諸多安全威脅議題尚未解決的前提下，如何提供一套有效率的安全通訊機制，實為重大的挑戰。
本研究藉由深入分析兩篇知名的國際期刊論文之安全度與效能評估，並發現此兩篇論文當中的金鑰協議協定（Key agreement protocol）無法抵抗已選擇協定攻擊(Chosen protocol attack)，更甚之，舉凡竊取金鑰假冒合法身份 (Key-compromise impersonation)與使用者誤認分享金鑰(Unknown key-share)等在金鑰協議協定研究中扮演重要角色的安全特性也都無法具備。在協定流程的安全分析中，本研究針對協定的流程瑕疵給予適當的修改建議與因應對策，此外，根據效能評估的數據顯示，安全傳輸策略的採用將取決於資料傳輸時的節點個數。

As VANETs (Vehicular Ad Hoc NETworks) promptly becomes one of the most promising applications in MANETs (Mobile Ad hoc NETworks), the nature of the data security vulnerability and privacy invasion of VANETs are also concerned by the individuals and organizations at the same time. Due to the self-organizing and decentralized topology, and high-speed movement characteristics, how to provide an efficient and secure communication scheme for VANETs is still an ongoing effort while many open security issues are still unsolved. In this study, we analyze the security and performance that two famous published communication schemes proposed by Raya & Hubaux (2007) and Wang et al (2008) on VANETs. From the security analysis, we point out that these two schemes are insecure against chosen protocol attack and key-compromise impersonation attack, and cannot achieve unknown key-share properties. We propose countermeasures for security enhancement. In addition, we further investigate the robustness and efficiency of these two communication schemes. According to the performance evaluation, we make suggestions for efficiency improvement of secure communication scheme on VANETs.

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