Wireless Network Security
By Stephen Bucaro
Anyone with a wireless capable computer knows that, by default, many wireless networks
are configured to be open connections. This means that anyone within range can connect to
the network. Even if a wireless network is configured properly, it's still less secure than
a wired network, because you can't physically secure the transmission media (airspace).
This makes it much easier for a hacker with a packet sniffer, sitting outside in the
parking lot, to break in.
Wireless networks use the IEEE (Institute of Electrical and Electronics Engineers) 802.11
standard. The first 802.11 standard, created in 1997, supported a maximum bandwidth of
only 2 Mbps (million bits per second). In July 1999 the IEEE created the 802.11b standard,
which supports a maximum bandwidth of 11 Mbps.
At the same time 802.11b was created, IEEE extended the original 802.11 standard to
support a maximum bandwidth of 54 Mbps, and called it 802.11a. But because 802.11b products
were lower cost than 802.11a, 802.11b became much more popular than did 802.11a.
Because 802.11a and 802.11b use different frequencies, the two technologies are incompatible
with each other. In the 2002 the 802.11g standard was developed. 802.11g supports a maximum
bandwidth of 54 Mbps, and is backwards compatible with 802.11b. That means 802.11g and 802.11b
wireless products can communicate, although at the lower 11 Mbps frequency.
WEP (Wired Equivalent Privacy) is a security method that is part of the 802.11 standard.
WEP uses a secret network key that is shared between the mobile station (wireless notebook
computer) and the access point. The network key is used to encrypt packets before they are
transmitted, and an integrity check ensures that packets were not modified in transit.
WEP uses a shared static encryption key that is shared between all mobile stations and
access points it is more susceptible to discovery than a security method that uses a randomly
generated single-use key. In response to WEP's low level of security, IEEE released the
802.11i wireless security protocol.
802.11i uses EAP (Extensible Authentication Protocol). With 802.11i a mobile station issues
a request to the access point. The access point acts as a proxy between the remote access
server and the mobile station. The 802.11i authentication protocol involves multiple
requests between the mobile station and the remote access server in order to authenticate
each other. They then communicate using the AES (Advanced Encryption Standard).
Before the IEEE completed the 802.11i standard, the Wi-Fi Alliance, a non-profit organization
dedicated to ensuring the interoperability and security of wireless devices, released WPA
(Wi-Fi Protected Access). WPA uses RC4 encryption, a technique that weaves multiple keys
as long as 2048 bits into the data stream. After the release of the IEEE 802.11i standard,
the Wi-Fi Alliance released WPA2 which is compatible with both the 802.11i standard and WPA.
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