TABLE OF CONTENTS Bluetooth is a low-cost, low-power, short-range radio link for wireless connectivity between mobile devices and wireless area networks and local area networks (WAN/LAN) access points. It includes both a hardware specification and software architecture. Bluetooth operates in the unlicensed 2.4 GHz ISM band, and this fact is both a strength and liability. But because numerous other wireless devices and protocols also operate in this band, Bluetooth has been plagued by interference problems. To solve them, Bluetooth designers turned to frequency-hopping solutions where they encountered another set of problems. Some countries have a narrower ISM band than others, and Bluetooth devices developed to operate in these countries are incompatible with Bluetooth devices elsewhere.
Despite these hurdles, Bluetooth proponents still get giddy with the numerous possibilities Bluetooth offers for mobile applications. In fact, few people would contest the vision. But Bluetooth is off to a bumpy start with incomplete interoperability, high costs, and slow development cycles. That means we ve yet to see the breadth of implementation that will test security measures and yield significant experience with the security model. In this chapter we ll look at security provisions based on specifications, architectures, and extrapolations from wireless communications technologies with similar provisions.
Bluetooth has three security modes, the lowest having no security mechanisms, and the highest enforcing authentication, authorization, and encryption at the linklevel. The intermediate level enforces authentication and encryption selectively through a mechanism known as the security manager. Authentication uses the SAFER+ block cipher, and encryption of data between...
