NETGEAR CG814W, Справочное руководство

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Reference Manual for the Model CG814W Wireless Cable Modem Gateway
B-16 Networks, Routing, and Firewall Basics
Overview of WEP Parameters
Before enabling WEP on an 802.11b network, you must first consider what type of encryption you
require and the key size you want to use. Typically, there are three WEP Encryption options
available for 802.11b products:
1. Do Not Use WEP: The 802.11b network does not encrypt data. For authentication purposes, the
network uses Open System Authentication.
2. Use WEP for 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 Open System
Authentication.
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.