What are four features of WPA? (Choose four.)

What are four features of WPA? (Choose four.)
A . a larger initialization vector, increased to 48 bits
B . a message integrity check protocol to prevent forgeries
C . authenticated key management using 802.1X
D . support for a key caching mechanism
E . unicast and broadcast key management
F . requires AES-CCMP

View Answer

Answer: ABCE

Explanation:

TKIP and the related WPA standard implement three new security features to address security problems encountered in WEP protected networks. First, TKIP implements a key mixing function that combines the secret root key with the initialization vector before passing it to the RC4 initialization. WEP, in comparison, merely concatenated the initialization vector to the root key, and passed this value to the RC4 routine. This permitted the vast majority of the RC4 based WEP related key attacks. Second, WPA implements a sequence counter to protect against replay attacks. Packets received out of order will be rejected by the access point. Finally, TKIP implements a 64-bit Message Integrity Check (MIC). To be able to run on legacy WEP hardware with minor upgrades, TKIP uses RC4 as its cipher. TKIP also provides a rekeying mechanism. TKIP ensures that every data packet is sent with a unique encryption key. Key mixing increases the complexity of decoding the keys by giving an attacker substantially less data that has been encrypted using any one key. WPA2 also implements a new message integrity code, MIC. The message integrity check prevents forged packets from being accepted. Under WEP it was possible to alter a packet whose content was known even if it had not been decrypted.

http://en.wikipedia.org/wiki/Temporal_Key_Integrity_Protocol http://documentation.netgear.com/reference/fra/wireless/WirelessNetworkingBasics-3-14.html