First, please keep in mind that I am a bit fuzy on the internal workings of EFS, but this is from what I remebmer... don't quote me on any of this..

edit: Also note that I've heard sources on both sides saying that file transfers from one Filesystem to the next would be encrypted still, and other sources say that they would no longer be encrypted. So I'm afraid I can't be much more help


ss2chef is correct here. Moving or copying EFS files to another file system removes the encryption, but backing them up preserves the encryption, this is because the encryption is not actually encryption, it is "We will protect and encrypt, but only if EFS is running and active." So it's half-ass encryption.

I know it doesn't make much sense acosapo, but that's how EFS works. It will encrypt as long as the EFS is running and the file system is active. If a file is copied to another file system that is not running EFS it loses it's encryption because there is nothing left to -continue- the encryption process. So going from NTFS EFS to FAt32 would completely remove all encryption. Actually the word remove is bad because we assume that the file stays encrypted during EFS. That isn't correct. The file is "Granted" encryption ability while EFS is running, and when EFS isn't active on that filesystem, that ability is gone.

WARNING, THEORY!! : In fact, in theory even moving it to another EFS active filesystem should still break the encryption merely because the file would then have to have a different encryption key for this new filesystem, and thus have no encryption after the file transfer.


A good article on EFS in general:

http://www.winntmag.com/Articles/Ind...&Key=Internals