Reference Manual for the 54 Mbps Wireless Travel Router WGR101
Wireless Networking Basics
D-7
February 2005 (202-10034-03)
Key Size and Configuration
The IEEE 802.11 standard supports two types of WEP encryption: 40-bit and 128-bit.
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 user-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.
128-bit encryption is stronger than 40-bit encryption, but 128-bit encryption may not be available
outside of the United States due to U.S. export regulations.
When configured for 40-bit encryption, 802.11 products typically support up to four WEP Keys.
Each 40-bit WEP Key is expressed as 5 sets of two hexadecimal digits (0-9 and A-F). For
example, “12 34 56 78 90” is a 40-bit WEP Key.
When configured for 128-bit encryption, 802.11b products typically support four WEP Keys but
some manufacturers support only one 128-bit key. The 128-bit WEP Key is expressed as 13 sets of
two hexadecimal digits (0-9 and A-F). For example, “12 34 56 78 90 AB CD EF 12 34 56 78 90”
is a 128-bit WEP Key.
Typically, 802.11 access points can store up to four 128-bit WEP Keys but some 802.11 client
adapters can only store one. Therefore, make sure that your 802.11 access and client adapters
configurations match.
Whatever keys you enter for an AP, you must also enter the same keys for the client adapter in the
same order. In other words, WEP key 1 on the AP must match WEP key 1 on the client adapter,
WEP key 2 on the AP must match WEP key 2 on the client adapter, etc.
Note:
The AP and the client adapters can have different default WEP Keys as long as the keys are
in the same order. In other words, the AP can use WEP key 2 as its default key to transmit while a
client adapter can use WEP key 3 as its default key to transmit. The two devices will communicate
as long as the AP’s WEP key 2 is the same as the client’s WEP key 2 and the AP’s WEP key 3 is
the same as the client’s WEP key 3.
