It's all in one html file, so it will work disconnected from the internet. Download or save the page, turn off your internet, open it in a browser, and encrypt

It's all in one html file, so it will work disconnected from the internet. Download or save the page, turn off your internet, open it in a browser, and encrypt with peace of mind (although the javascript could still use off-line storage and then next time you're online on the page access it, I guess).