EFS is almost useful

If a student had turned in the EFS design as a project I may have given them a C+ or B-. It has all the hallmarks of good encryption design that was then taken by a committee and developed into a product. I wrote this little program to solve the problem of how to copy EFS encrypted files to a USB key drive. If you just drag the files to the USB drive then Windows ‘helpfully’ decrypts them for you without asking. In any serious encryption system the default should be to *not* decrypt data without explicit permission, sigh!

Copy “sendtoEFS.exe” into the “sendto” folder in your Windows profile so that it can be used from the Explorer menu. It uses the Windows API call “OpenEncryptedFileRaw” to access the raw encrypted data and not transparently decrypt it; the PDF file explains.