Gigabyte GN-AP02G User Manual page 26

One of the biggest drawbacks to traditional WEP security is
that changing the encryption key is optional. Even if you do
switch encryption keys from time to time, there is no option for
globally rekeying all access points and all wireless NICs.
Instead, rekeying is a tedious manual process and is
completely impractical for large organizations. After all, the
instant you rekey an access point, none of the clients will be
able to access it until they are also rekeyed.
But with WPA, the rekeying of global encryption keys is
required. In the case of unicast traffic, the encryption key is
changed after every frame using Temporary Key Integrity
Protocol (TKIP). This protocol allows key changes to occur on
a frame by frame basis and to be automatically synchronized
between the access point and the wireless client. Global
rekeying works by advertising the new keys to wireless
clients.
The TKIP is really the heart and soul of WPA security. TKIP
replaces WEP encryption. And although WEP is optional in
standard Wi-Fi, TKIP is required in WPA. The TKIP encryption
algorithm is stronger than the one used by WEP but works by
using the same hardware-based calculation mechanisms WEP
uses.
The TKIP protocol actually has several functions. First, it
determines which encryption keys will be used and then
verifies the client security configuration. Second, it is
responsible for changing the unicast encryption key for each
frame. Finally, TKIP sets a unique starting key for each
authenticated client that is using a preshared key.
AES (Advanced Encryption Standard), A standard, sponsored
by the National Institute of Standards and Technology, for
protecting data through encryption. AES supports key sizes of
128 bits, 192 bits and 256 bits and will serve as a replacement
for the Data Encryption Standard (DES), which has a key size
of 56 bits. In addition to the increased security that comes with
larger key sizes, AES can encrypt data much faster than
Triple-DES, a DES enhancement that which essentially
encrypts a message or document three times.
WPA PSK WPA use of a preshared key.