Abstract: Wireless networking is a double-edged sword. The interception of wireless communications has existed as a problem when sensitive data are exchanged. In order to protect the data from eavesdroppers, various forms of encryption have been used to scramble the data. The IEEE 802.11 standard for wireless network describes an encryption protocol called Wired Equivalent Privacy (WEP). The goal of WEP is to make WLAN communication as secure as wired LAN data transmissions would be, by protecting link-layer communication from eavesdropping and other attacks. To protect wireless networking against attacks, understanding both the vulnerabilities that exist and how attackers employ tools to identify WLANs, capture network traffic and break WEP encryption keys, is crucial to exploit the vulnerabilities of the wireless network.In this thesis there is a presentation for several weaknesses in the WEP Protocol. Also there is an analysis of why these vulnerabilities exist and how they can be exploited by an attacker to circumvent the privacy of a network. The attacks target both the inherent weaknesses in the protocol (the key scheduling of RC4), as well as implementation issues such as the length of keys, weak keys, and finally the WEP authentication protocol. A new hybrid algorithm for decoding WEP key is designed. The new algorithm makes use of IVs collision and statistical analysis method which reduce the required time to find the key.Practical experiments have been conducted using Linux Shell and Perl language. The secret WEP key was obtained successfully in different lengths (64 and 128). Many tests on key were done, and the obtained results were satisfactory in term of accuracy and speed. Also there is a presentation of solutions to improve WEP and Strengthening IEEE 802.11 in order to protect the wireless communication.