Given: During 802.

In Cisco LEAP (Lightweight EAP), the username is sent in clear text as part of the 802.1X authentication process. LEAP uses a challenge/response authentication mechanism that is susceptible to offline dictionary attacks because the attacker only needs to know the username and capture the challenge/response exchange to perform brute-force guessing of passwords. The username is used in generating the hash for the authentication exchange, making its disclosure critical for an attacker.

Incorrect:

A. PACs are used in EAP-FAST, not LEAP.

C. The 4-Way Handshake nonces are unrelated to the username.

D. While dictionary files may include username/password combos, the cryptographic significance in LEAP is due to the challenge/response mechanism.