Hardware Implementation of Bluetooth Security

S ecurity in pervasive computing is a complex issue that has been the subject of negative publicity in recent years due to poor implementations (such as the Wired Equivalent Privacy protocol used by IEEE 802.11). Many low-level protocols are not secure, and the use of more secure high-level protocols is limited by the processing capabilities of mobile devices. Bluetooth could enhance and extend pervasive applications because it is well suited to the power requirements of mobile applications (see the “Bluetooth” sidebar). Furthermore, it offers methods for generating keys, authenticating users, and encrypting data. Most single-chip Bluetooth baseband implementations, which include a low-performance general-purpose processor, implement only the data encryption in hardware. However, in time-critical applications requiring a fast connection and in devices with processing constraints, implementing key generation and authentication in the hardware (rather than software) is also preferable. To improve performance in these applications, we use an efficient implementation of the Safer+ (Secure And Fast Encryption Routine) algorithm, which reduces the resource requirements.