ZyXEL Communications ZyXEL ZyAIR G-260, User Manual

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ZyXEL G-260 User’s Guide
27 Chapter 2 Wireless LAN Network
The encryption mechanisms used for WPA(2) and WPA(2)-PSK are the same. The only
difference between the two is that WPA(2)-PSK uses a simple common password, instead of
user-specific credentials. The common-password approach makes WPA(2)-PSK susceptible to
brute-force password-guessing attacks but it's still an improvement over WEP as it employs an
easier-to-use, consistent, single, alphanumeric password.
2.2.4 WPA(2)-PSK Application Example
A WPA(2)s-PSK application looks as follows.
1 First enter identical passwords into the AP and all wireless clients. The Pre-Shared Key
(PSK) must consist of between 8 and 63 ASCII characters (including spaces and
symbols).
2 The AP checks each client's password and (only) allows it to join the network if it
matches its password.
3 The AP derives and distributes keys to the wireless clients.
4 The AP and wireless clients use the TKIP encryption process to encrypt data exchanged
between them.
Figure 8 WPA-PSK Authentication
2.2.5 WPA with RADIUS Application Example
You need the IP address of the RADIUS server, its port number (default is 1812), and the
RADIUS shared secret. A WPA-RADIUS application example with an external RADIUS
server looks as follows. "A" is the RADIUS server. "DS" is the distribution system.
1 The AP passes the wireless client's authentication request to the RADIUS server.
2 The RADIUS server then checks the user's identification against its database and grants
or denies network access accordingly.
3 The RADIUS server distributes a Pairwise Master Key (PMK) key to the AP that then
sets up a key hierarchy and management system, using the pair-wise key to dynamically
generate unique data encryption keys to encrypt every data packet that is wirelessly
communicated between the AP and the wireless clients.