Bluetooth is a low-power wireless technology intended to replace cables and wires and let multiple devices discover and talk to each other at speeds up to 1M bit/sec over a range of roughly 30 feet.
Bluetooth communications are encrypted for security. When two Bluetooth devices try to establish a link, one of the first things they do is exchange keys confirming their identities. If the keys don't match, the two devices won't talk to each other.
Under Bluetooth 1.0b, the two devices could get into an irreconcilable race condition during the initial link negotiation. The devices would execute the algorithm to generate the key, but each device would generate a different key. The problem revolves around timing.
Generating the correct key depends on which device initiates the conversation (the master) and how fast the responding device (the slave) replies to the master's communications. If the slave can process information faster than the master, the ensuing race condition can leave each device calculating that it is the master. Based on that error, the devices fail to generate matching keys.
Bluetooth 1.1 rectifies this problem by more thoroughly defining the steps required for device authentication. Specifically, Version 1.1 requires that each device confirm its role in the master/slave relationship by reconciling and/or acknowledging which device initiated interaction.
It's named for the Danish king Harald Blåtand a.k.a. Bluetooth, who united Denmark and Norway in the 10th century.
From Bluetooth 1.1 addresses earlier flaws, Network World Tech Update, 08/13/01
Additional resources
Bluetooth.com
Bluetooth SIG's site.
Ultra-low-power Bluetooth: the new wireless frontier
Network World Tech Update.
