WPA Encryption Explained

By PseudoRandomDragon
in Essential Guides

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Grand Master

PseudoRandomDragon

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When you have a wireless network, it is your responsibility to make it as difficult as possible for someone else to gain access to it. After all, if someone does get in they can find out what your surfing, gain access to your computers and mess with router settings...or just use your internet connection.

Disabling SSID broadcasting and using MAC filtering is great, but can't stop someone from sniffing your traffic. WEP encryption provies a basic level of encryption, but can be cracked in under 10min.

So if you want a secure wireless network, there isn't a way around it, you need to use WPA.

Requirements

You need hardware and/or firmware/drivers that allow the use of WPA. Every wireless-G hardware out there has some form of WPA on it, but a firmware or driver update can get WPA on your older wireless-b equipment as well. Hardware that has been sold before 2003 generally need to be replaced.

Different Types

WPA Radius Authentication - Your typical home user wont use this, unless you want to setup a radius server. This server works with WPA to pass different keys to each user. I'm not going to go into how to set this up.

WPA PSK - PSK stands for Pre-Shared Key and is most commonly used by home users. The user must have a certain password to enter the network. PSK can be used with either AES or TKIP, depending on what your hardware can support. It is important that you choose a strong password to prevent against dictionary attacks.

AES - An algorithm that requires special hardware support to use. It is stronger, but a firmware/driver update won't get you AES.

TKIP - This system changes the key every specified amount of time to prevent cracking attempts. You can usually adjust how often it changes in the router/AP settings. This does not mean it changes your password, just the key.

WPA2 - The new WPA standard that uses a stronger algorithm, but is not backwards compatable with older hardware.

Making sure you got the software

Being that WinXP is the only OS that officially supports WPA2, you need to rely on 3rd party vendors for support, which is usually delivered.

Most of the time, when you install a driver for the wireless card, a special WPA driver will be installed with it. You can see it by going into the network/dialup connections in the control panel and looking at the properties of the card. It might be called something like "AEGIS WPA Protocol" or "WPA Security Protocol". Note that you cannot install updates to these protocols seperately from the drivers, your card requires specific WPA protocols to work.

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Your router should have options for WPA in it's settings. If it does not, a firmware update could allow WPA to be enabled. Check the router's webpage to see if there is one.

If you do get a firmware update that enables WPA, I highly recommend that you restore your router's settings to factory default after upgrading the firmware. If I had known to do that I woulda saved myself a lot of trouble. :pinch:

Setting it up

First connect to the router with a patch cable rather than wirelessly. Setting up the router is easier that way. Login the router, go to the wireless security part. WPA-PSK is the type of encryption you want to use. After selecting PSK, you might get an option to either use AES or TKIP. If you had to upgrade any software to get WPA, then you probably have to use TKIP since AES requires hardware that natively supports WPA. After the selections have been made, you must choose a passphrase. Try to have it in the range of 10 to 25 characters. Once the passphrase is set, enter the same information in the wireless network card and you should be set.

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Troubleshooting...

If WPA wont work:

1) Make sure that you have all the types and the passphrases matched exactly.

2) Try turning off/on the router or restarting.

3) If you are using the wireless config utility that comes with WinXP, try using the one that came with the card instead. You can set it by going into the properties of the network connection and unchecking "use windows to configure my wireless settings"

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4) Sometimes using obscure characters like ąĈ??? can work against you in the passphrase.

5) If signal strength is lower than 9dB, then the connection is flaky with WPA.

6) Check to make sure the router is on fire. Fires usually interfere with the router's function.

7) If there are other wireless networks on the same channel in your area, change the channel to some different value.

8) Avoid generic drivers and firmware.

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Grand Master

PseudoRandomDragon

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  Relativity_17 said:
Is there any software available for Windows that can tell whether you've successfully disabled SSID broadcasting on your router?

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No, that requires the wireless utility that comes with your wireless card. All utilties come with a thing that views available wireless networks. Good adapters can show all the wireless networks in the area, if they have encryption, their signal strengh and their network name (or lack thereof). I think you can trust that SSID broadcasting is disabled and as long as you didn't leave it at "netgear" or "linksys", you're fine.

Experienced

Zxian

Posted
Posted

Considering that 3 of my neighbours have unencrypted networks, I'm not all too worried about someone getting into my network. The computers themselves are only open to each other, since their IPs are statically assigned from the router.

I'll look into it later on during the summer though... just for kicks.

Grand Master

Vice

Posted
Posted

Just a quick tip if your card does not support WPA look for the chipset that the card is and look on the internet for a company (like Dlink or Netgear) that uses the same chipset that does support WPA in there driver, install there driver over your card and you now have all there features.

My card an Asus 802.11G with only WEP 128bit encryption is convinced its a D-Link card and I now have WPA WPA-PSK WEP and so on.

Grand Master

Evolution

Posted
Posted
  WinMacLin said:
Just a quick tip if your card does not support WPA look for the chipset that the card is and look on the internet for a company (like Dlink or Netgear) that uses the same chipset that does support WPA in there driver, install there driver over your card and you now have all there features.

My card an Asus 802.11G with only WEP 128bit encryption is convinced its a D-Link card and I now have WPA WPA-PSK WEP and so on.

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Indeed :) Here's a link that might be useful to some. i.e. Toshiba Wireless LAN Adapter users can simply download the latest Agere driver.

  • 2 weeks later...
Grand Master

PseudoRandomDragon

Posted
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Posted
  kaffra said:
nice guide, i just got my netgear wireless router today. So wpa is better to have then wep?

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Tons better. Wep can be cracked in like 15min tops. WPA is a lot stronger so long as you have a good password.

  Quote
Does the user have to always key in a password to access the network(if wpa is used?)

No.

Neowinian

marshallbanana

Posted
Posted (edited)

Thanks for this guide, but I was wondering if you knew anything about steps to fix another (seemingly common) problem.

I recently set up a home wireless network in my fiance's parents' house, and set up with WPA-PSK. The router was a Linksys, I can't recall the exact model off the top of my head, but it was 802.11b only. (The notebook is capable of G, but for their purposes, that isn't really necessary, and the B router was $5 after rebate at Best Buy.)

The notebook is a Toshiba Satellite (don't remember the model either, sorry) with integrated B/G wireless, and was purchased in July of 2004. The notebook has successfully logged onto other WPA-PSK networks without having this problem. (There is a small coffee house with wi-fi that uses PSK we have connected in)

Logging in itself isn't the problem, however, every so often (probably when the key is reset), the connection is dropped, and we have to manually reconnect. Right now, the network is set to WEP, but they would really prefer to have WPA, and we cannot figure out how to correct this issue.

Just wondered if anyone had any ideas of how to start troubleshooting this, thanks!

Edit: Used TKIP when setting up

Edited by marshallbanana
Grand Master

PseudoRandomDragon

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  marshallbanana said:
Logging in itself isn't the problem, however, every so often (probably when the key is reset), the connection is dropped, and we have to manually reconnect. Right now, the network is set to WEP, but they would really prefer to have WPA, and we cannot figure out how to correct this issue.

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Well your in luck because I had just about the exact same problem, with almost the same hardware (linksys router + toshiba satellite). After upgrading the firmware of the router itself, I switched to WPA, but the connection keeped dropping. I found out, after much difficulty, that it was caused by the router switching between WPA and WEP. Resetting the router settings fixed the problem. Hopefully it will fix it for you as well.

Neowinian

marshallbanana

Posted
Posted

Well, WPA-PSK was available on the router without a firmware update, so I haven't done so. Would it be a good idea to try this first?

I'm not sure that resetting the router settings will do much, since the only settings changed out of the box were those concerning the SSID and setting up the encryption. I suppose it's worth a try :D

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