Authentication And Wep Encryption - NETGEAR HR314 Reference Manual

Reference Manual for the Model HR314 802.11a Hi-Speed Wireless Router

Authentication and WEP Encryption

The absence of a physical connection between nodes makes the wireless links vulnerable to
eavesdropping and information theft. To provide a certain level of security, the IEEE 802.11
standard has defined two types of authentication methods, Open System and Shared Key. With
Open System authentication, a wireless PC can join any network and receive any messages that are
not encrypted. With Shared Key authentication, only those PCs that possess the correct
authentication key can join the network. By default, IEEE 802.11 wireless devices operate in an
Open System network.
Wired Equivalent Privacy (WEP) data encryption is utilized when the wireless nodes or access
points are configured to operate in Shared Key authentication mode. There are three shared key
methods implemented in NETGEAR's 802.11a solutions: the standard based 40-bit WEP data
encryption and 128-bit WEP data encryption plus the extended 152-bit WEP data encryption.
The 64-bit WEP data encryption method, allows for a five-character (40-bit) input. Additionally,
24 factory-set bits are added to the forty-bit input to generate a 64-bit encryption key. (The 24
factory-set bits are not user-configurable). This encryption key will be used to encrypt/decrypt all
data transmitted via the wireless interface. Some vendors refer to the 64-bit WEP data encryption
as 40-bit WEP data encryption since the user-configurable portion of the encryption key is 40 bits
wide.
The 128-bit WEP data encryption method consists of 104 configurable bits and the 152-bit WEP
data encryption method consists of 128 configurable bits. Similar to the forty-bit WEP data
encryption method, the remaining 24 bits are factory set and not user configurable. Some vendors
allow passphrases to be entered instead of the cryptic hexadecimal characters to ease encryption
key entry.
Figure B-3shows examples of key sizes and content for the different WEP methods:
Table B-3. WEP Key Sizes and Content
# of
Encryption Key
Hexadecimal
Size
Digits
64-bit 10
(24+40)
128-bit 26
(24+104)
152-bit 32
(24+128)
B-12
Example of Hexadecimal Key Content
4C72F08AE1
4C72F08AE19D57A3FF6B260037
4C72F08AE19D57A3FF6B26003715DAC2
Network and Routing Basics