Since wi-fi was first introduced, a number of security techniques have been used to protect wi-fi networks from unauthorised users and to ensure that the data transmitted across them is secure. The most common methods are based on encryption, using a key known only to the nodes in the wireless network.
The first of these mechanisms was called Wired Equivalent Privacy (WEP), which (as the name suggests) aimed to provide confidentiality comparable to that of a wired network. Since 2001, a number of serious problems have been identified in WEP that allow the encryption key to be computed within a few minutes, using readily available software. Many wireless devices still support WEP to ensure compatibility with older equipment such as old modems, but wherever possible users should switch to a more modern form of encryption.
At the present time, the recommended security mechanism for wi-fi networks is wi-fi Protected Access 2 (WPA2), which uses a more secure key to encrypt the transmitted data. This security mechanism has become the default configuration for wi-fi networks, and must be supported by all wi-fi devices in order for them to be compliant with the 802.11 standard.
Using wireless networks securely
Use the network connection tool on your computer to identify how many wireless networks are within range of your current location.
How many of them use secure connections? If your home wireless network is not configured to use WPA2, find out how to set this up and make sure to do this. The user manual for your wireless router or your internet service provider’s website should have information that will help.
Consider how you connect to the internet when you are on the move. Do you connect to your home wi-fi network, your mobile service provider, the free wi-fi in a coffee shop?
How do I safely use public WiFi networks?
Public WiFi networks are useful, but as you learned earlier in the course, the data transmitted across these networks are not protected by encryption and therefore can be easily intercepted by attackers. Therefore, it is prudent to avoid accessing important services using public WiFi networks, unless you are sure that the service provider (e.g., your online banking service) uses an additional layer on encryption to keep the network traffic between your device and their servers protected.
When you visit a website, the secure hypertext transfer protocol (HTTPS) is used to encrypt the data moving between your computer and the computer from which the website content is being delivered. This is usually indicated by websites showing the ‘padlock’ icon in the browser and that the identity of the website matches the digital certificate issued for this particular website address. It is possible that an attacker manages to obtain a valid certificate for a web address like https://www.goog1e.com (note the ‘1’ instead of ‘l’) and visitors to this address will see a closed padlock and might think they are securely communicating with Google’s website. Performing such an attack requires convincing the certificate issuing organisation that the website actually belongs to the requestor – something that is usually quite hard to do. However, in 2011 a hacker managed to access an account at one of the certification authorities and issued certificates to a number of web domains. To prevent the certificates from being misused, web browser software had to be updated to stop accepting certificates issued by the certificate authority that was hacked.
So the presence of a padlock icon and using HTTPS is not a perfect guarantee of safety online – you still have to be careful to check that the web address of the site you are visiting is correct, and keep your browser software up to date.
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