What is the key size for RC4 when used with WPA?

The key size for RC4 when used with WPA (Wi-Fi Protected Access) is indeed 128 bits. RC4 is a stream cipher that was widely used in various cryptographic protocols, and in the context of WPA, it is employed to secure wireless communications. The 128-bit key size is significant because it provides a level of security that was considered robust at the time WPA was implemented.

Choosing a 128-bit key allows for a large number of possible keys, which enhances security against brute-force attack attempts. Given that WPA was designed to improve upon the weaknesses found in WEP (Wired Equivalent Privacy), using a longer key length like 128 bits was crucial in providing better security for wireless networks. It is important to note that while RC4 is effective for encryption, it has known vulnerabilities, leading to the evolution of further protocols like WPA2, which recommend stronger methods of encryption and key management.

In summary, the selection of 128 bits as the key size for RC4 in WPA represents a balance between security needs and the technological capabilities of the time, emphasizing mobile and wireless security in a more reliable manner compared to older standards.