Stuff And Things
There is a great addition to emacs called epa which uses your GnuPG set up encrypt your org file based on public key encryption.
Easy to set up and works great.
See here for more details.
Just for completeness, assuming you have setup gpg, add the following to your .emacs:(require 'epa)And then if you open any file with a .gpg extension you get prompted for which person in your gnupg database you wish to encrypt for using their public key. If you do NOT select a destination user then it does symmetrical encryption and so prompts you for a passphrase which you will need to open the file again. Excellent.