臺灣博碩士論文加值系統

隨著無線通訊的普及化，通訊品質及資訊安全變成一個重要的課題。802.11n是一種現今被普遍使用的WLAN(Wireless Local Area Network) 技術，其中包含了封包聚合技術(Frame Aggregation)及其他技術來提升傳輸速度。另外也包含WPA2(Wi-Fi Protected Access 2) 這種安全機制以保護傳輸過程中資料不被竊取或竄改。但是這兩個機制卻沒有被同時考慮，因此當使用者開起WPA2 來進行保護時，傳輸的速率會急速下降。
在本篇論文中，我們提出運用分割式計數器模式密碼塊鏈消息完整碼協議的複合結合式自動回覆請求 (Aggregated Hybrid Automatic Repeat Request Mechanism with Fragmentation Counter Mode with CBC-MAC Protocol, AH-FCCMP)使得用戶在保證安全傳輸的情況下，也能有良好的傳輸品質。這個機制利用改變CCMP的運算方式，使得資料傳輸與加解密運算可以同步運算，以達到整體運算時間的減少。模擬結果顯示我們提出的AH-FCCMP機制能達到比傳統機制高的系統傳輸量，並保證資訊安全上的需求。

Since the spread of wireless communication, it is more and more important about transmission rate and information safety. 802.11n is one of the famous technology in WLAN (Wireless Local Area Network), which boosts its own transmission speed by frame aggregation (FA) and other core technologies. Furthermore, it also contains WPA2(Wi-Fi Protected Access 2), which provides secure mechanism for preventing data eavesdropped or stolen during transmission. However, these two features are not taken into consideration together. If users switch on WPA2 for secure purpose during 802.11n transmission, the system throughput will nosedive.
In this thesis, we propose AH-FCCMP (Aggregated Hybrid Automatic Repeat Request Mechanism with Fragmentation Counter Mode with CBC-MAC Protocol), which provides high transmission speed under data transfer safety. This mechanism change the architecture of CCMP for computing encryption/decryption and receiving data in parallel, so the total service time can be reduced. The simulation result shows that AH-FCCMP provides higher system throughput than the original one and the requirement of information security.

Mandarin Abstract i
English Abstract ii
Contents iii
List of Figures iv
List of Tables v
Chapter 1 - Introduction 1
Chapter 2 - Related work 3
2.1 IEEE 802.11 family 3
2.1.1 IEEE 802.11n 4
2.1.2 802.11i 7
2.2 Cryptography and Data Encryption 7
2.2.1 Block Cipher Mode 8
2.2.2 Advanced Encryption Standard 9
Chapter 3 - Proposed Algorithm 13
3.1 Aggregated Hybrid-ARQ 13
3.2 Fragmentation CCMP 17
3.2.1 Replay Attack in different packets in FCCMP 19
3.2.2 Replay Attack in the same packets in FCCMP 20
3.2.3 FCCMP Algorithm 22
3.3 AH-ARQ with FCCMP 23
Chapter 4 - Simulation 27
4.1 System configurations 27
4.2 Performance comparison under different numbers of MPDUs 28
4.3 Performance comparison under different RS-codec schemes 30
4.4 Performance comparison under different MCSs 33
Chapter 5 - Conclusion 37
Bibliography 39

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