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Appendix: Dell TrueMobile 1180 Wireless USB Adapter User's Guide
Page 2 of 3
All wireless clients and Wireless Broadband Routers in a WLAN must use the same network name.
Encryption
In a WLAN, wireless clients and Wireless Broadband Routers send and receive information through the air.
Without implementing security, it is possible for an unauthorized person to intercept the information.
A common way of implementing security and protecting information is encryption. Encryption applies a set of
instructions, called an algorithm, to information. The instructions combine the plain or clear text of information
with a sequence of hexadecimal numbers, called an encryption key.
Before transmitting information over the airwaves, the wireless client or Wireless Broadband Router encrypts
or scrambles the information. The Wireless Broadband Router or wireless client receiving the information
uses the same key to decrypt or unscramble the information. The information is only readable to WLAN
devices that have the correct encryption key. The longer the key is, the stronger the encryption.
The form of data encryption used by the Wireless Broadband Router is called Wired Equivalent Privacy
(WEP). When encryption is enabled, you must set the WEP key in the client to match the WEP key used by
the Wireless Broadband Router because you will ONLY associate to Wireless Broadband Routers that have a
matching WEP Key. For added security, change the encryption key often. WEP, or encryption, is an optional
feature that can be enabled or disabled.
There are two WEP encryption methods: 40(64)-bit and 104(128)-bit. 40-bit and 64-bit encryption is identical
similarly 104-bit and 128-bit encryption is identical. Some vendors use the term 40-bit; others use 64-bit. A
wireless device that claims to have 40-bit encryption interoperates with a device that claims to have 64-bit
encryption, and vice versa. A 40(64)-bit key consists of 10 hexadecimal numbers in five two-digit groups,
arrayed as follows:
Example Key #1: 1A:2E:3F:11:18
A 128-bit hexadecimal key has several trillion times as many possible combinations than a 40(64)-bit key. It
consists of 26 hexadecimal numbers arranged in thirteen two-digit groups, arrayed as follows:
Example Key #1: 1A:2D:3E:5F:4A:22:19:77:91:A1:B2:C3:D8
The examples above are for hexadecimal key format. Keys may also be in ASCII format. ASCII characters
consist of any numbers or letters in upper or lower case. The key may be 40(64)-bit ASCII, which consists of
five characters (for example: 12Abc). The key may also be 104(128)-bit ASCII, which consists of thirteen
characters (for example: AbCdEf1234567). Note the case of the letters is important and "abcde" is not the
same as "ABCDE".
All wireless clients and Wireless Broadband Routers in a WLAN must use the same encryption method and
key. The following two examples stress how important this point is.
Example 1
The encryption method for a Wireless Broadband Router is 40(64)-bit. The method for a wireless client is 128-
bit encryption. The client and Wireless Broadband Router cannot communicate with each other, even though
the selected key is the same. To resolve this problem, set the Wireless Broadband Router to use 128-bit
encryption.
Example 2
The encryption method is the same for the Wireless Broadband Router and wireless client. You select key 1
for the Wireless Broadband Router and key 2 for the wireless client. The wireless client cannot communicate
with the WLAN. To resolve this problem, select key 1 for the wireless client.
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30-9-2003
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