User Manual

www.moxa.com [e-mail]19
Understanding Industrial WLAN – IEEE 802.11
Encryption
The science of encryption or, in more down-to-earth terms, the making and breaking of codes, is one of the
most crucial aspects of WLAN technology. This is because the radio waves used to transmit data packets
between your computer and the wireless access point can pass through walls, floors, and other barriers.
People who use laptops that have a wireless LAN card will know this first-hand, since it is often possible to
pick up signals from wireless access points located in nearby apartments. Using a password to restrict entry
to your network may not provide enough protection, since a reasonably clever person can still intercept your
data packets. In fact, if the person intercepting the wireless data is more than reasonably clever, he or she
may also be able to download and read the contents of the packets.
As illustrated in the schematic below, wireless encryption has evolved from WEP, which was released in
1999, to the 802.11i standard, more commonly referred to as WPA2.
The Evolution of Wireless Encryption
WPA2
WPA2 is the second generation of WPA. The primary difference between WPA and WPA2 is the technology
used for data encryption. WPA uses Temporal Key Integrity Protocol (TKIP) for data encryption, whereas WPA2
uses Advanced Encryption Standard (AES), a stronger encryption technology suitable for industries that require
highly secure networks.
WPA
Wi-Fi Protected Access (WPA) is a stronger security method that was created in response to the flaws
discovered in WEP. It was intended as an intermediate measure until further 802.11i security measures were
developed. When implemented with authentication methods such as RADIUS, WPA is considered secure
enough for all but the most sensitive enterprise applications. For most home and small business use, an
effective level of security can be obtained by using WPA with a pre-shared key (PSK) that is shared by all users.
802.1X
802.1X is an authentication method that prevents unauthorized users from entering the network. It is used with
WPA to form a complete WLAN security system. On many wireless systems, users either log into individual
access points, or can freely enter the wireless network but cannot get further without additional authentication.
802.1X makes users authenticate to the wireless network itself, not an individual AP or another other level like a
VPN. This is more secure, as unauthorized traffic can be denied right at the AP.
WEP
Wired Equivalent Privacy (WEP) provides a basic level of security to prevent unauthorized access to the
network and protect wireless data. Static shared keys (fixed length alphanumeric/hexadecimal strings) are
used to encrypt data and are manually distributed to all wireless stations that want to use the wireless network.
WEP has been found to have serious flaws and is not recommended for networks that require a high level of
security. For more robust wireless security, most access points support Wi-Fi Protected Access (WPA or WPA2)
for improved data encryption and user authentication.