有鑑於無線網路所提供的機動性，只要使用者處於基地台的服務範圍，就能使用相關的網路資源；具有高度的便利性，使得無線網路的使用人數逐年增加。此外，不論是在固定(有線)網路或者無線網路下，網路安全始終是一門相當重要的議題。本篇論文即針對無線網路中的加密機制WEP所遭遇到的安全性上的漏洞，包括附加於封包後的初始向量為明文、無法抵抗重送攻擊及可靠性等問題，提出最佳化的解決方法。相較於遵守IEEE 802.11i標準所規範的WPA，改良後的WEP僅需要執行軟體上的更新，而不須硬體上的變動。

The mobility offered by wireless networks enables users to have the access to related network resources if they are within served area of access points. Owing to the convenience of wireless networks, the population of it users are getting more and more. In addition, network security is always a vital issue for either the Ethernet or wireless networks. This paper presented an optimized solution to eliminate the security holes of WEP (Wired Equivalent Privacy) which includes the plaintext transmission of IV, vulnerable to replay attacks and the reliability problem. As compared with WPA (Wi-Fi Protected Access) which complies.

中文摘要................................................III
Abstract..............................................IV
誌謝....................................................V
Figure List.......................................VIII
Table List.................................................IX

Chapter 1： Introduction...........................................1
1.1 ackground..............................................1
1.2 Motivation and Purpose.............................................2
1.3 Structure.............................................3
Chapter 2： Related Works………………………………5
2.1 Wired Equivalent Privacy (WEP)………………..5
2.1.1 Concepts……………………………………………….5
2.1.2 WEP Cryptographic Operations……………………….7
2.2 The Keyed-Hash Message Authentication Code (HMAC)................................................11
2.2.1 Concepts………………………………………………11
2.2.2 HMAC Specification………………………………….12
2.2.3 HMAC Algorithm……………………………………..15
Chapter 3： Overview of WEP…………………………...22
3.1 WEP Weakness……………………………………………...22
3.2 Brief Review of eWEP Scheme……………………………..26
Chapter 4： Optimized WEP Scheme (O-WEP)………...30
4.1 Notation and Nomenclature in O-WEP………………30
4.2 O-WEP Cryptographic Operations…………………33
Chapter 5： Security Analyses……………………………36
5.1 Security Improved……………………………………………36
Chapter 6： Conclusion and future work………………..40
6.1 Conclusion……………………………………………40
6.2 Future works…………………………………………40
Reference………………………………………………………..41

Reference
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