Home » Cisco » 200-355 » Which key is established using the four-way handshake during the WPA authentication process?
Which key is established using the four-way handshake during the WPA authentication process?
A. Pairwise MasterKey
B. Pairwise Multiple Key
C. Pairwise Session Key
D. Pairwise Transient Key
E. Pairwise Transverse Key
Correct Answer: D
Explanation/Reference:
Explanation:
The authentication process leaves two considerations: the access point (AP) still needs to authenticate itself to the clientstation (STA), and keys to encrypt the traffic need to be derived. The earlier EAP exchange or WPA2-PSK configuration has provided the shared secret key PMK (Pairwise Master Key). To derive the PMK from the WPA-PSK, the PSK is put through PBKDF2-SHA1 as the cryptographic hash function. This key is, however, designed to last the entire session and should be exposed as little as possible. Therefore the four-way handshake is used to establish another key called the PTK (Pairwise Transient Key). The PTK is generated by concatenating the following attributes: PMK, AP nonce (ANonce), STA nonce (SNonce), AP MAC address, and STA MAC address. The product is then put through a pseudo random function.
http://en.wikipedia.org/wiki/IEEE_802.11i-2004