Which security protocol is considered highly vulnerable to attack due to its short initialization vector?

Wired Equivalent Privacy (WEP) is highly vulnerable to attack primarily because of its weak encryption mechanisms, particularly its use of a short initialization vector (IV). The IV, which is a key component in the encryption process, is only 24 bits long in WEP. This limited size makes it susceptible to various types of attacks, such as IV collisions and brute-force attacks.

When attackers can observe enough traffic and capture enough IVs, they can exploit the weaknesses inherent in how WEP generates and uses these initialization vectors to break the encryption and gain access to sensitive data on the network. As a result, WEP is considered insecure and has largely been replaced by more robust security protocols, such as Wi-Fi Protected Access (WPA) and Wi-Fi Protected Access 2 (WPA2), which implement stronger encryption methods and longer key sizes to mitigate these vulnerabilities.