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Reference Manual for the MR814v2 Cable/DSL Wireless Router
D-6 Wireless Networking Basics
3. Use WEP for Authentication and Encryption: A transmitting 802.11b device encrypts the
data portion of every packet it sends using a configured WEP Key. The receiving 802.11b device
decrypts the data using the same WEP Key. For authentication purposes, the 802.11b network uses
Shared Key Authentication.
Note: Some 802.11b access points also support Use WEP for Authentication Only (Shared Key
Authentication without data encryption).
Key Size
The IEEE 802.11b 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, 802.11b 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.
Note: Typically, 802.11b access points can store up to four 128-bit WEP Keys but some 802.11b
client adapters can only store one. Therefore, make sure that your 802.11b access and client
adapters configurations match.