You have to be offline, that is to say, not connected to the Internet whenever you work with kn Secrets in earnest. Please read the following guidelines very carefully.
Using kn Secrets in online mode is ok only when not really using it in earnest — for example, when you have directed your browser to the knsecrets.online website just to obtain a first impression of kn Secrets. Then you must use non-secrets to learn how kn secrets works. You could use something like "Trying out Secure Secret Sharing" as free-text input, for instance. Otherwise, be aware that using kn Secrets in earnest requires putting secrets on screen by filling in input fields on your browser page. Also, your browser page will have to display Secure Shares for you to be able to note them down. User interaction of this kind always increases the risk that hackers with access to your computer might steal the secret or, equivalently, Secure Shares that you have generated. For this reason, you must follow the guidelines that are stated below whenever you use kn Secrets to transform any real secret into Secure Shares, or the other way round. We cannot absolutely guarantee that they will prevent hackers from obtaining secrets or Secure Shares — nothing ever will, unfortunately — but they should go some way towards reducing the hacker risk.
1) Use an open-source browser and make sure to have updated your browser to the newest version.
2) Preferably, run your browser on an open-source operating system.
3) Download the .zip archive that contains the offline version of kn Secrets. Unzip it and find the file whose file name is "index.html". Double-click it to start kn Secrets in offline mode.
4) Disconnect your computer physically from the Internet while using kn Secrets offline. Depending on how your Internet connection is set up, turn off your wifi router, at the very least turn off wifi on your computer, and disconnect any Ethernet cable that might be plugged into your computer.
5) Disconnect all unnecessary external devices from your computer.
6) Make sure to not have any browser tabs open that are not from kn Secrets.
7) It is strongly recommended to store Secure Shares by noting them down manually with pen and paper, or to click the PDF button and print them directly from your browser's PDF previewer.
8) If, despite the previous point, you decide to use a some kind of text processor to print Secure Shares, then you must take care to avoid any Secure Shares getting stored on your system. Open a text editor and copy-and-paste Secure Shares into the editor one after the other using the "copy" button displayed on each Secure Share, each time using the editor's print function followed by deleting the Secure Share from the editing pane. Under all circumstances, you must avoid any Secure Share ending up on your system's disk storage. Do not use the editor's "Save" or "Save as" functions and, also, make sure that the editor does not generate any backup files automatically. Analogously to using an open-source operating system and an open-source browser, your best bet is to use an open-source editor where you have made sure that that does not happen.
9) kn Secrets uses input elements that are not usually subject to browsers remembering any input provided. This kind of functionality is commonly known as "browser caching." If you do worry about browser caching, then you need to clear out your browser's cache whenever you have finished using kn Secrets. To this end, close all browser tabs and the browser itself, then restart the browser and go to the privacy and security section in its settings menu. Clearing out browser caches should be available in this section. Once browser caches have been cleared, you still have to apply a secure sweep to every disk drive that belongs to your system given that you take the — entirely theoretical — caching risk seriously. Modern solid-state drives (SSD), the kind of disk storage used on practically all computers nowadays, require special procedures if a disk sweep is to be carried out. You will probably have to visit the website of your SSD's manufacturer to learn how. Never apply any traditional "file shredding" method to an SSD as that will most probably damage it or may even render it inoperable. Even with proper procedures being applied, an SSD disk sweep may lead to your whole system having to be re-installed.
10) Never use any mobile device or tablet to work with kn Secrets in earnest.
11) Keep the offline version on secure, backed-up storage to be able to recover secrets in case knsecrets.online goes down at any time.
12) Read the FAQ to learn more.