> ONE OF THE EXCELLENT FEATURES of new Windows devices is that disk encryption
> is built-in and turned on by default, protecting your data in case your device is lost
> or stolen. But what is less well-known is that, if you are like most users and login to
> Windows 10 using your Microsoft account, your computer automatically uploaded a
> copy of your recovery key to Microsoft’s servers, probably without your knowledge
> and without an option to opt out.

Source: https://theintercept.com/2015/12/28/recently-bought-a-windows-computer-microsoft-probably-has-your-encryption-key/

Of course, what's not so excellent a feature is what this means for recovering data from an encrypted disk that a user may have had no need to be encrypted.