Snabb och säker roaming i WLAN

Sammanfattning: This thesis investigates how Ericsson AB should do to achieve fast and secure handover when roaming in a WLAN. It also provides a security analysis of the system that the wireless access point is part of. The reason for this is that Ericsson is selling an access point called the ABS 2200 aimed at the public hotspot market. The premise was that they wanted a standardized way of handling the roaming issue. At the outset the 802.11F standard looked like a good alternative (in fact the only standardized alternative). Towards last stages of the work though, it was discovered that the 802.11F standard is no longer supported by IEEE. Despite this fact, the conclusion is that secure and fast roaming can be attained if 802.11F is combined with the security standard 802.11i. The security analysis concludes that Denial Of Service is a major threat to WLAN hotspots. It also points out the link between the access point and authentication server is the weakest link in the system. The recommendation is that this link receives an additional layer of protection through IPsec withESP. The algorithm recommendations for ESP are AES for confidentiality and SHA-1 for integrity. This thesis can also be used as a primer on security in WLAN and contains an extensive glossary making it useful as a reference when reading 802.11 standards.