Q: What is BitLocker Network Unlock?

A: Windows 8 introduces BitLocker Network Unlock, which provides an additional protector method for BitLocker.

Typically with BitLocker, in addition to the Trusted Platform Module (TPM), using it in certain modes requires user intervention, such as authentication mode, where a startup key must be typed when booting the BitLocker-protected machine, and USB key mode, where the user must insert a USB drive.

BitLocker Network Unlock allows automatic access to the BitLocker key needed to unlock the volume. That automatic access occurs over the network when the machine boots, avoiding any manual steps. It essentially works in a very similar way to the TPM+startup key BitLocker method, except the key is being sent over the network.

There are several requirements for this functionality:

At the time of its release, Microsoft will have step-by-step documentation for this process. For now, however, a beta document "Understand and Troubleshoot BitLocker in Windows Server "8" Beta"  also walks through the process.