The study of the defects in WEP protocol

• Main Authors: Chen-Chung Lu, 盧承忠
• Other Authors: Jenn-Shing Wang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/z9bh8e

碩士 === 國立臺北科技大學 === 電機工程系所 === 94 === Concerning the installation convenience and the mobility of hosts, the adoption of wireless local area network, which mainly chooses IEEE 802.11 for communication protocol and usually uses WEP for packet encryption, is getting more and more popular. But caused by the inherent WEP flaw, the generated secret key lost its effectiveness, i.e. the attacker can easily retrieve the plaintext without knowing the secret key. In this paper, we proposed a method to crack WEP aimed at this flaw. First, we could imagine the first 40 bytes of the key sequence according to the characteristic of WEP. Then we extended this key sequence to the length of maximum transmission unit. Finally, the dictionary for all key sequences had been built up corresponding to every Initialization Vector. After implementation, we proved the effectiveness of this method.