I've noticed several threads here complaining about difficulties unlocking whole disk encrypted (WDE) computers (laptops, I presume) using external keyboards...
I just thought I would share that usually for around $100, there are many sources of keyboard loggers out there...
I don't know how common it is to see keyboard logger attacks out in the wild, but I do know that there are various manufacturers and distributors actively marketing these devices, so my assumption is that amateur use of these devices will likely only increase with time. A keyboard logger has got to be the easiest way to defeat encryption when physical access to the keyboard is available.
A keyboard logger is a dongle-style pass-through device about the size of a small USB drive. The keyboard plugs into the logger device, with the device in turn plugging into the victim's computer. The logger device is small and may not be noticed unless you are specifically looking for it and know what you are looking for. They are available for PS2 keyboards as well. There are also keyboards available with a keyboard logger hidden directly inside the keyboard. Some of these devices even have built-in wifi, so that the perp can retrieve data wirelessly, without the need to physically recover the device.
With a keyboard logger installed, from the moment the computer is powered on, before it has even started booting, everything that gets typed on the external keyboard gets saved by the logger device, and continues to be saved for later retrieval even after the computer has been powered back off. (Ironically, even if the docking station is for whatever reason not properly sending the keystrokes to the computer, you can bet that the logger device is capturing all keystrokes from the external keyboard...)
The data captured by a keyboard logger of course includes any PGP passphrases typed into the external keyboard.
Laptop keyboards can not be intercepted by any of the commonly available keyboard loggers because laptop keyboards probably don't use USB and certainly don't use standard USB connectors. Also, assuming that a compatible logger could be procured in the first place, physically installing a data logger into a laptop keyboard would be fairly technically challenging and would take a minimum of several minutes alone with the laptop. By contrast, someone needs no technical skill and only 10 to 15 seconds alone with your docking station to install a standard keyboard logger onto any keyboard cable that is plugged into the docking station.
The best way to avoid the threat of keyboard loggers is to minimize the use of external keyboards when a laptop keyboard is available, especially when typing something sensitive like a PGP passphrase.
If the PGP WDE drivers can in any way allow the administrator to require use of the laptop keyboard, or at least encourage the user to use the laptop keyboard for typing their passphrase instead of using an external keyboard, this would be a good thing, because generally speaking the laptop is less likely to be compromised than is the peripheral keyboard with its unencrypted connection to the computer/docking station.
It may be interesting to note, also, that while a wireless keyboard may encrypt the wireless signal, this would not defeat a keyboard logger if the keyboard utilizes a wireless receiver which plugs into the computer/docking station, because the keyboard logger could be inserted between the receiver and the computer/docking station.
I hope this info is of interest to anyone out there.