The physics behind wi-fi and wi-fi security?

[Jacob West]

I'm doing a project on wi-fi in physics class, and i'm having a lot of trouble with the physics behind wi-fi security. I have a few questions.

1. Do clients and access points communicate with each other through radio waves? If so, is information and data packets carried "on" the radio wave? (In other words, is information contained within the radio waves themselves?)

2. Does each client have it's own unique frequency that can be blocked by wi-fi security? In other words, how does the router prevent access from any client?

3. What are the problems with WEP and WPA? What makes a WPA2 better than the others?

In general, how are waves and physics involved in wi-fi and the security of it.

Thanks!
@Afraid of Flu

Thanks scooter, it's not like I haven't looked at that page a million times already. -_-
@xNand
Thank you for answering. I sort of understand the wikipedia page, but it doesn't really say anything about the physics of Wi-Fi, it basically only says that its transmitted through radio waves.

[Afraid of Flu]

http://en.wikipedia.org/wiki/Wi-Fi

[xNand]

Put simply, everything sent over WIFI can be seen by anyone with a WIFI adapter that support promiscious mode, but whether they can make anything of the packets is up to whether encryption is being used on the wireless access point or not.

No offence but if you can't understand the WIFI wiki page then it'll be hard for me to explain the types of encryptions and their key lengths etc,,

[Link H]

All the wi-fi systems use radio waves. A wi-fi frequency is allocated to each device when it connects with the access point. This frequency is called a carrier, because it does not encode the information. The modulation (information) is combined with the carrier before transmission and separated from it after reception.

The modulation, using frequencies much lower than the carrier, encodes a digital data stream. Before being modulated, the data stream is encrypted to prevent other devices which know the carrier frequency and modulation from eavesdropping on the information.

The receiver of the information must know how to decrypt it in order to use it.

Physics is important in the transmission and reception of the radio signal, and in the construction of the electronic circuits, but the encryption and decryption is just math.

A router might have several mechanisms which permit or deny access. These might include any or all of the following:

1) IP address
2) MAC address
3) Wifi Security Key (any of WPS PIN, WPA passphrase, or Network Key)
4) Encryption method


Generally what makes one encryption technique better than another is the size of the keys used and the identified or potential existence of flaws in them.