Wired Equivalent Privacy (WEP)
WEP is a security algorithm for IEEE 802.11 wireless networks. It was introduced with the original 802.11 standards ratified in 1997, and it was majorly done to provide data confidentiality which was not in traditional wired networks. WEP is recognizable by its key of 10 or 26 hexadecimal digits (40 or 104 bits). It was of great use and was often the first security choice presented to users by router configuration tools over the others.
In the year 2003, the Wi-Fi Alliance made a statement that WEP had been superseded by Wi-Fi Protected Access (WPA). In 2004, with the ratification of the full 802.11i standard (i.e. WPA2), the IEEE declared that both WEP-40 and WEP-104 were deprecated.
WEP uses the algorithm of RC4 encryption. Here, each packet is encrypted at the router or access point, and then it is sent out. When the client receives this packet, the client will be allowed to transform it back to its original form because the key was provided. So, the router encrypts the packet and sens it, and the client receives it and decrypts it. If the client sends something to the router, the activity takes place. It will first encrypt the packet using a key, send it to the router, and the router will be able to decrypt it because it has the key. if an attacker captures the packet in the middle, then they will get the packet, but they wouldn’t be able to see the contents of the packet because they do not have the key.
Each packet that is sent out has a unique stream of keys. The unique keystream is generated using a 24- bit IV (Initialization Vector). An initialization vector is a random number that is sent into each packet in plain text form, without being encrypted. If a hacker captures the packet, they will not be able to read the packet content because it is encrypted, but they can read the IV in plain text form.
The main challenge with the IV is that it is sent in the pain text and it is very short(only 24- bit). In an occupied network, there will be a large number of packets sent out. At this time 24-bit number is not enough. The IV will start repeating on a busy network. The repeated IVs can be used to find the key stream. This makes WEP exposed to statistical attacks.
To determine the key stream we can use a tool called as aircrack-ng. This tool is used to find the key stream. Once we have enough repeated IV, then it will also be able to crack WEP and give us the key to the network.
WEP was the only encryption protocol available to 802.11a and 802.11b devices invented before the WPA standard, which was available for 802.11g devices. However, some 802.11b devices were later provided with firmware or software updates to enable WPA, and newer devices had it built-in.