When you're using a wireless network, everything you send
is going across the air in radio waves
which means that everybody who's in your local area
can hear everything that you happen to be sending.
Obviously we need to be able to encrypt data then going
over these wireless networks.
We don't want somebody pulling our information out of the air
and seeing the information that we're sending.
Fortunately our wireless standards
allow us methods to be able to encrypt everything going
over these wireless networks.
And the only way you'd be able to know what is in that data
is if you also are part of that wireless network.
Only the people that have the right password
would be able to transmit information
on that wireless network and be able to listen
to the information that was sent.
There have been a number of different encryption
methodologies used on wireless networks through the years.
The only one you should really be using these days
is WPA2, but let's talk about all of the different wireless
encryption that's been in use through the years
and really get an understanding of the ones you should use
and the ones that you should not use.
When our 802.11 technologies were first introduced,
they included an encryption mechanism called WEP.
WEP stands for Wired Equivalent Privacy
and it provided a couple of different types of encryption.
We could enable 64-bit keys for our encryption or 128-bit keys.
With a name like Wired Equivalent Privacy,
it sounds like we'd have exactly the same privacy
on our wireless network as we would on a wired network.
Well, unfortunately, that was in name only.
We found some cryptographic vulnerabilities in WEP in 2001.
As it turns out, some of the data
that was being sent over the WEP network
was "strongly non-random."
That is definitely not what you want if you want
to keep information private.
This means that if you were able to collect enough information
from the wireless network, you'd be
able to piece this together and understand
what the key actually was.
And of course, once you had the key,
you had access to everything on that particular wireless
network.
The rule these days is not to use WEP.
You can find a WEP key in a matter of minutes
with today's technology, and generally, the devices
that you would purchase and put into your network
these days don't even give you the option
to run WEP because of these cryptographic vulnerabilities.
When these problems with WEP were discovered,
we had to come up with a different way
of encrypting and protecting the data
over our wireless networks.
And so we came up with a standard
called WPA, this stands for Wi-Fi Protected Access.
WPA used something called RC4 with TKIP.
This is the Temporal Key Integrity Protocol.
RC4 is the hashing method to use to encrypt the information
and TKIP was the way that we kept the keys
and sent information over the network.
This uses a larger initialization vector,
had an encrypted hash associated with it.
A lot of this that was normally in the clear or easily
determined on a WEP network was much more
difficult to see with WPA.
Every packet got a unique encryption key
and we were able to keep all of the data
on our wireless networks encrypted now using WPA.
But this was a methodology for encrypting that we
could make even stronger.
This was more of a short term workaround.
We came up with an update to WPA called WPA2.
The certification for this began in about 2004.
The RC4 cipher was replaced with AES,
that stands for Advanced Encryption Standard,
and we added CCMP instead of TKIP.
CCMP is the Counter Mode with Cipher Block Chaining Message
Authentication Code Protocol.
By combining this update to the protocol,
we were able to create a much more secure method.
And even today, WPA2 is the standard encryption
that we use on our wireless networks.
When you're configuring an access point, especially one
you might use at home, you're probably
configuring it with WPA2 or something called
WPA2 PSK for pre-shared key.
But you might also see an option for WPA2 Enterprise.
This is when you're adding 802.1X network access control
where you might have some access control mechanisms
or authentication servers in your environment.
And you're allowing people access to the network
if they log in with their normal username and password.
Another method of wireless network security
is something called MAC filtering.
This is referring to the Media Access Control
address that's the hardware address that we
have in our wireless devices.
MAC filtering provides us with a way to allow or disallow access
to the wireless network based on the hardware
address of these devices.
We can make a big list and have only the devices in our list
gain access to the wireless network.
This might be very useful to keep neighbors out
of your network or to make sure that only people that
are authorized to be on the network
are on the wireless network.
And maybe we keep visitors out of our corporate wireless
network.
Unfortunately, it's very easy to determine
what MAC addresses are in use in a particular area.
A simple network analysis scan of the area
can show you every one using the wireless network.
And these MAC addresses can then be
spoofed using the capabilities that
are either built into the driver that you're using.
There's also even free open-source software
available to craft packets however you would like.
This is a security mechanism we often refer to as security
through obscurity.
We think by making something more difficult to do
that it's somehow more secure.
And of course, that's not true at all.
Security through obscurity is no type of security.
MAC filtering itself is only a very limited access control
mechanism and we should not rely on it
to provide any type of wireless security.