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 ( 40/104/232 bits ) is concatenated with the initialisation vector ( 24 bits ) resulting in a 64/128/256 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

We can set up the Access Point by Web configurator.

- Setting up the Access Point from Web GUI

G-4100 hold up to 4 WEP Keys. You have to specify one of the 4 keys as default Key which be used to encrypt wireless data transmission.
Key settings

WEP Key type | Example
64-bit WEP with 5 characters | Key1= 2e3f4 Key2= 5y7js Key3= 24fg7 Key4= 98jui
64-bit WEP with 10 hexadecimal digits ('0-9', 'A-F') | Key1= 123456789A Key2= 23456789AB Key3= 3456789ABC Key4= 456789ABCD
128-bit WEP with 13 characters | Key1= 2e3f4w345ytre Key2= 5y7jse8r4i038 Key3= 24fg70okx3fr7 Key4= 98jui2wss35u4
128-bit WEP with 26 hexadecimal digits ('0-9', 'A-F') | Key1= 112233445566778899AABBCDEF Key2= 2233445566778899AABBCCDDEE Key3= 3344556677889900AABBCCDDFF Key4= 44556677889900AABBCCDDEEFF

Select one of the WEP key as default Key to encrypt wireless data transmission.
The receiver will use the corresponding key to decrypt the data.
For example, if access point use Key 3 to encrypt data, then station will use Key 3 to decrypt data.
So, the Key 3 of station has to equal to the Key 3 of access point.
Though access point use Key 3 as default key, but the station can use the other Key as its default key to encrypt wireless data transmission.

Access Point (encrypt data by Key 3) --------> Station (decrypt data by Key 3)

Access Point (decrypt data by Key 2) <-------- Station (encrypt data by Key 2)

In this case, access point transmits data to station which encrypt data by Key 3 of access point. The station will decrypt the data by its Key 3.

At the same time, when the station transmits data to access point which encrypt data by Key 2.
The access point will decrypt the data by its Key 2.

- 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 un check '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= lkasd
Key2= oueww
Key3= wopek
Key4= woppe

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

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