Shared Key Authentication - NETGEAR WG311 Installation Manual

Installation Guide for the NETGEAR 54 Mbps Wireless PCI Adapter WG311
1) Authentication request sent to AP
Client
attempting
to connect
3) Client connects to network
Figure 3-8: 802.11 open system authentication

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 802.11 network or Ethernet network.
This process is illustrated in below.
B-4
802.11b Authentication
Open System Steps
2) AP authenticates
Access Point
IN TER N ET W LA N LO CA L MODEL FVM318
ProSafeWirelessVPN Security Firewall
Cable/DSL LNK 100
PWR TEST
ACT Enable LNK/ACT
1 2 3 4 5 6 7 8
CSU/DSU
or DLS modem
Wireless Networking Basics