The Bluetooth wireless technology realizes a low-cost short-range wireless voice- and data-connection through radio propagation. Bluetooth also has a security architecture. In this paper, we focus on the key agreement protocol, which is the most critical part of this security architecture. Several security flaws have been identified within the Bluetooth protocols: an attacker can track users by monitoring the Bluetooth hardware address, all keys depend on a low-entropy shared secret (the PIN), there are some very easy to perform Denial of Service attacks. We propose a new initialization mechanism for the key agreement protocol of Bluetooth. This improved pairing protocol can be easily extended so that it will not only solve the dependency of the keys on the PIN, but also the location privacy problem and an important Denial of Service attack. Our solution is user friendly and energy-efficient, two essential features for Wireless Personal Area Networks (WPAN).