The key which fits to decrypt captured packets is the key used by wireless network to encrypt its entire wireless communication with its connected stations. To crack the WEP key, a hacker needs to capture sample packets not intended for his own network interface and run crack program to compare testing keys against WEP key bundled with captured packets in attempt of decryption. However, if one node sets its own network card into promiscuous mode it will also receive packets which are not addressed for its own MAC address. The same principle also applies for wireless networks.

Each host receives packets only intended for MAC address of its own interface. The basic principle is that communication between two nodes on the network is based on the MAC address. WEP ( Wired Equivalent Privacy ) is quite easy to crack as it uses only one key to encrypt all traffic. This can be done by sniffing a wireless network, capturing encrypted packets and running appropriate encryption cracking program in an attempt to decrypt captured data.

This article shortly describes simple steps on how to crack a wireless WEP key using aircrack-ng software.

Wireless network wep key cracker