Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

62 CHAPTER 4 Wireless Networking
WEP characteristics:
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WEP utilizes a shared-key authentication that allows for encryption and
decryption of wireless transmissions.
Up to four keys can be defined on an AP or a client, and they can be rotated
to add complexity for a higher security standard in the WLAN policy.
The driving force behind WEP was privacy. In cases that require high degrees
of security, other mechanisms should be utilized such as authentication,
access control, password protection, and virtual private networks (VPNs).
Despite its flaws, WEP still offers a better level of security than open wireless
connections.
EXAM WARNING
Most APs advertise that they support WEP in 64-bit encryption, but often the 128-bit option
is also supported. For corporate networks, 128-bit encryption-capable devices should be
considered as a minimum.
With data security enabled in a closed network, the settings on the client for the
SSID and the encryption keys must match the AP when attempting to associate
with the network or it will fail. WEP provides security and privacy in transmissions
held between the AP and the clients. Some of the other benefits of implementing
WEP include the following:
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All messages are encrypted using a CRC-32 checksum to provide some
degree of integrity.
Privacy is maintained through the RC4 encryption. Without possession of
the secret key, the message cannot be decrypted.
WEP is extremely easy to implement. All that is required is to set the
encryption key on the APs and on each client.
WEP provides a basic level of security for WLAN applications.
WEP keys are user-definable and unlimited. WEP keys can, and should, be
changed often.
EXAM WARNING
Do not confuse WAP and WEP. Although it may seem that WEP is the privacy system for
WAP, you should remember that WTLS is the privacy mechanism for WAP and WEP is the
privacy mechanism for 802.11 WLANs.
WPA AND WPA2
Because of the relative ease that WEP with a preshared key can be broken, the Wi-
Fi Alliance has created a new encryption standard called Wi-Fi protected access
(WPA). WPA enhances security over WEP by using the Temporal Key Integrity
Protocol (TKIP) to address some of the weaknesses of WEP including per-packet