Fingerprinting 802.11 devices has been proposed to identify devices in order to mitigate IEEE 802.11 weaknesses. However, important limitations prevent any real deployment. On the first hand, fingerprinting has a low accuracy when the devices have similar hardware and software. On the second hand, attackers may forge signatures to impersonate devices. The authors propose Diversity, a cooperative fingerprinting approach that improves accuracy of existing fingerprinting methods while relying only on off-the-shelf hardware. Diversity improves fingerprinting up to the reliable individual identification of identical 802.11 devices.