Shared Key Authentication - NETGEAR CG814W Reference Manual

Shared Key Authentication

The following steps occur when two devices use Shared Key Authentication:
The station sends an authentication request to the access point.
1.
The access point sends challenge text to the station.
2.
The station uses its configured 64-bit or 128-bit default key to encrypt the challenge text, and
3.
sends the encrypted text to the access point.
The access point decrypts the encrypted text using its configured WEP Key that corresponds
4.
to the station's default key. The access point compares the decrypted text with the original
challenge text. If the decrypted text matches the original challenge text, then the access point
and the station share the same WEP Key and the access point authenticates the station.
The station connects to the network.
5.
If the decrypted text does not match the original challenge text (i.e., the access point and station do
not share the same WEP Key), then the access point will refuse to authenticate the station and the
station will be unable to communicate with either the 802.11b network or Ethernet network.
This process is illustrated in below.
802.11b Authentication
Shared Key Steps
1) Authentication
request sent to AP
Client
3) Client encrypts
attempting
challenge text and
to connect
sends it back to AP
5) Client connects to network
Figure 6-5: 802.11b shared key authentication
Networks, Routing, and Firewall Basics
Reference Manual for the Model CG814W Wireless Cable Modem Gateway
2) AP sends challenge text
4) AP decrypts, and if correct,
authenticates client
Access Point
MODEL FVM318
IN TER N ET W LA N LO CA L
ProSafeWirelessVPN Security Firewall
Cable/DSL LNK 100
PWR TEST
ACT Enable LNK/ACT
1 2 3 4 5 6 7 8
Cable or
DLS modem
B-15