Using EFS File Shares and Web Folders Remotely
Web folders require less administrative effort and are more secure than file shares. Web folders can also securely store and deliver encrypted files over the Internet using standard HTTP file transfers. Using file shares for remote EFS operations requires a Windows 2000 or later domain environment. This is necessary because EFS must impersonate the user through Kerberos protocol delegation to encrypt or decrypt files for the user.
You can encrypt and decrypt files that are stored on network file shares or on Web Distributed Authoring and Versioning (WebDAV) Web folders. Web folders have many advantages compared to file shares, and Microsoft recommends the use of Web folders whenever possible for remote storage of encrypted files.