Stefan Mileschin

Windows 8.1 will automatically encrypt the storage on modern Windows PCs. This will help protect your files in case someone steals your laptop and tries to get at them, but has important ramifications for data recovery.

Previously, “BitLocker” was available on Professional and Enterprise editions of Windows, while “Device Encryption” was available on Windows RT and Windows Phone. Device encryption is included with all editions of Windows 8.1 — and it’s on by default.
When Your Hard Drive Will Be Encrypted

Windows 8.1 includes “Pervasive Device Encryption.” This works a bit differently from the standard BitLocker feature that’s been included in Professional, Enterprise, and Ultimate editions of Windows for the past few versions.

Before Windows 8.1 automatically enables Device Encryption, the following must be true:

The Windows device “must support connected standby and meet the Windows Hardware Certification Kit (HCK) requirements for TPM and SecureBoot on ConnectedStandby systems.” (Source) Older Windows PCs won’t support this feature, while new Windows 8.1 devices you pick up will have this feature enabled by default.
When Windows 8.1 installs cleanly and the computer is prepared, device encryption is “initialized” on the system drive and other internal drives. Windows uses a clear key at this point, which is removed later when the recovery key is successfully backed up.
The PC’s user must log in with a Microsoft account with administrator privileges or join the PC to a domain. If a Microsoft account is used, a recovery key will be backed up to Microsoft’s servers and encryption will be enabled. If a domain account is used, a recovery key will be backed up to Active Directory Domain Services and encryption will be enabled.

http://www.howtogeek.com/173592/wind...-need-to-know/