Vista has the option to encrypt and decrypt files by accessing the properties dialog. But there is a better and faster way to do it—just add these options to the context menu. Open the Registry editor and navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced 
In the right pane, create a new 32-bit DWORD value called Encryption Context Menu and give it a value of 1. Now whenever you rightclick
a file, you will see a new option,Encrypt, which will let you encrypt it
(along with the parent folder, if necessary). Once it’s encrypted, when you right-click on it, you will see the Decrypt option.
