Which of the following keys are types of pairwise transient key (PTK)? Each correct answer represents a complete solution. Choose all that apply.
A.
Temporal Key (TK)
B.
Key Encryption Key (KEK)
C.
Key Confirmation Key (KCK)
D.
STSL Transient Key (STK)
Explanation:
Following are the types of pairwise transient key (PTK):
Key Confirmation Key (KCK): Key Confirmation Key (KCK) provides data integrity during the 4-way handshake and group key handshake processes. It binds the pairwise master key (PMK) to the AP. Key Encryption Key (KEK): Key Encryption Key (KEK) provides data privacy during the 4-way handshake and group key handshake processes.
Temporal Key (TK): Temporal key (TK) encrypts and decrypts the MSDU payload of the IEEE 802.11 data frames between the client and the AP.Answer option D is incorrect. The STSL Transient Key (STK) is used in the peerkey handshake process.
What is Pairwise Transient Key?
Pairwise Transient Key (PTK) is a 64-byte key that comprises the following:
16 bytes of EAPOL-Key Confirmation Key (KCK): This key is used to compute MIC on WPA EAPOL Key message. 16 bytes of EAPOL-Key Encryption Key (KEK): AP uses this key to encrypt additional data sent (in the ‘Key Data’ field) to the client. 16 bytes of Temporal Key (TK): This key is used to encrypt/decrypt unicast data packets. 8 bytes of Michael MIC Authenticator Tx Key: This key is used to compute MIC on unicast data packets transmitted by the AP. 8 bytes of Michael MIC Authenticator Rx Key: This key is used to compute MIC on unicast data packets transmitted by the station.Pairwise Transient Key is derived from the pairwise master key (PMK), Authenticator address (AA), Supplicant address
(SPA), Authenticator nonce (A Nonce), and Supplicant nonce (S Nonce) using pseudo-random function (PRF).