This is a file encryption web app contained in a single .html file (so you can save it and use it offline). It's output is a single .html file containing both the decryption software and your encrypted files.
So you mean if I live in North Korea and I want to encrypt something on my computer off the grid and THEN go on the grid and send ONLY the encrypted data I can do that? And then the recipient can download the encrypted data and THEN go off the grid and read our secret plot against kim jong un unnoticedwe can....brilliant