Setup WEP (Wired Equivalent Privacy)

· Introduction

· Setting up the Access Point

· Setting up the Station

Introduction

The 802.11 standard describes the communication that occurs in wireless LANs.

The Wired Equivalent Privacy (WEP) algorithm is used to protect wireless communication from eavesdropping, because wireless transmissions are easier to intercept than transmissions over wired networks, and wireless is a shared medium, everything that is transmitted or received over a wireless network can be intercepted.

WEP relies on a secret key that is shared between a mobile station (e.g. a laptop with a wireless Ethernet card) and an access point (i.e. a base station). The secret key is used to encrypt packets before they are transmitted, and an integrity check is used to ensure that packages are not modified during the transition. The standard does not discuss how the shared key is established. In practice, most installations use a single key that is shared between all mobile stations and access points APs.

WEP employs the key encryption algorithm, Ron's Code 4 Pseudo Random Number Generator (RC4 PRNG). The same key is used to encrypt and decrypt the data.

WEP has defences against this attack. To avoid encrypting two cipher texts with the same key stream, an Initialisation Vector (IV) is used to augment the shared WEP key (secret key) and produce a different RC4 key for each packet, the IV is also included in the package. WEP key (secret key) are available in two types, 64-bits and 128-bits. Many times you will see them referenced as 40-bits and 104-bits instead. The reson for this misnomer is that the WEP key ( 40/104 bits ) is concatenated with the initialisation vector ( 24 bits ) resulting in a 64/128 bit total key size.

Setting up the Access Point

Most access points and clients have the ability to hold up to 4 WEP keys simultaneously. You need to specify one of the 4 keys as default Key for data encryption. To set up the Access Point, you will need to set the one of the following parameters:

- 64-bit WEP key (secret key) with 5 characters
- 64-bit WEP key (secret key) with 10 hexadecimal digits
- 128-bit WEP key (secret key) with 13 characters
- 128-bit WEP key (secret key) with 26 hexadecimal digits

Setting up the Access Point with Web configurator

Key settings

Select one WEP key as default key to encrypt wireless data transmission.

Setting up the Station

1. Double click on the utility icon in your windows task bar or right click the utility icon then select 'Show Config Utility'.

The utility will pop up on your windows screen.

Note: If the utility icon doesn't exist in your task bar, click Start -> Programs -> IEEE802.11b WLAN Card -> IEEE802.11b WLAN Card.

2. Select the 'Encryption' tab.
Select encryption type correspond with access point.
Set up 4 Keys which correspond with the WEP Keys of access point.
And select on WEP key as default key to encrypt wireless data transmission.

Key settings
The WEP Encryption type of station has to equal to the access point.
Check 'ASCII' field for characters WEP key or uncheck 'ASCII' field for Hexadecimal digits WEP key.
Hexadecimal digits don't need to preceded by '0x'.
For example,
64-bits with characters WEP key :
Key1= 2e3f4
Key2= 5y7js
Key3= 24fg7
Key4= 98jui

64-bits with hexadecimal digits WEP key :
Key1= 123456789A
Key2= 23456789AB
Key3= 3456789ABC
Key4= 456789ABCD

All contents copyright (c) 2006 ZyXEL Communications Corporation.