Wireless Security.pdf - PDF Archive

Wireless Embedded System Security 607
MSCHAPv2
EAP
EAP-GTC
TLS
PEAPv0, EAP-TTLS
PEAPv1
EAP-TLS
EAP-SIM
EAP
802.1X
802.11b/g
EAP was originally implemented for WPA2, and at the time the only EAP-variant required
for Wi-Fi Alliance compliance (needed to use the trademarked Wi-Fi name and logo on a
product) was called EAP-TLS, TLS being the Transport Layer Security protocol. However,
the number of EAP variants has grown considerably, as various vendors have created their
own mechanisms, all slightly different. Now, there are a total of 5 variants required to
be compliant: EAP-TLS, EAP-TTLS/MSCHAPv2 8 (TTLS is simply “Tunnelled TLS ” ),
PEAPv0/MSCHAPv2 (Protected EAP, which establishes a TLS connection over which
EAP methods are used), PEAPv1/EAP-GTC (an EAP variant developed Cisco), and
EAP-SIM which is essentially authentication using SIM cards for the telecom industry.
In any case, Wi-Fi authentication is a dynamic and complex field and keeping up with it
can be quite a challenge (by the time you are reading this it is likely that there have been
a number of new protocols added and compliance requirements have changed). If you are
interested in learning more about the wide array of authentication mechanisms for Wi-Fi,
there are numerous online resources and there are even a few books on the subject. A good
place to start is the Wi-Fi Alliance website itself: www.wi-fi.org . Figure 23.2 shows the
relationships between the different authentication mechanisms used by Wi-Fi.
23.1.5 Drowning in Acronyms
Figure 23.2 : Wi-Fi authentication mechanisms
The alphabet soup of Wi-Fi authentication protocols begs one important question: What
do we need to support? Well, like we have talked about before, we need to adapt the
protocol to our application. If you are implementing the latest and greatest consumer
gadget and you must be compliant with every wireless access point under the sun, you
8
MSCHAP is a variant of the PPP CHAP protocol developed by Microsoft. MSCHAPv2 is
described in RFC 2759.
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