Finding Bluetooth link key in Windows 7, to double pair a device on dualboot computer
- by Ilari Kajaste
How can I dig up the Bluetooth link key for a paired device in Windows 7? Is this something that is dependent on the Bluetooth stack I'm using (Toshiba), or is there a generic place to store these in Windows 7?
Note: I'm not talking about the six-digit code usually typed by the user during pairing - that is worthless since it's discarded after pairing process. What I mean is the 128-bit link key that the devices exchange during pairing, and use thereafter to encrypt all their Bluetooth traffic.
Background:
I dualboot Windows 7 / Ubuntu on my laptop, and I would like to have my phone paired to both OS's. Since the dualbooting computer has only one Bluetooth adapter and thus only one Bluetooth address, I cannot do two pairings to the phone, since on the second pairing (Windows) the phone just replaces the previous pairing (Linux) to the same Bluetooth address.
A thread on Ubuntu forums pointed me to what I have to do - pair first on Linux, then on Windows, and then replace the link key on Linux side with the one Windows negotiated.
I can find the Linux side pairing key from /var/lib/Bluetooth/[BD_ADDR]/linkkeys - no problems there.
However, on Windows side I can't find the key. According to the forum post, on Windows side the key should be in SYSTEM\ControlSet002\services\BTHPORT\Parameters\Keys\[BD_ADDR] but while that registry key does exist, it has no subkeys. (And a similar registry path in ControlSet001 didn't have any subkeys either.)
One thing I've been instructed to do is to capture all events during pairing with Sysinternals Process Monitor. I did this, but I haven't been able to find any useful information from the captured events, not even by exporting the data to a huge XML and grepping that with the BD_ADDRs (with or without colons).
So how could I find the link key for a paired device in Windows 7?
Some reference information: Wikipedia: Bluetooth, Security Now: Bluetooth security
