Here at Hackaday, we pride ourselves on bringing you the latest and greatest projects for your viewing pleasure. But sometimes we come across a creation so interesting that we find ourselves compelled to write about it, even if it’s already been hanging around the Internet for years. This may or may not be due to the fact that we just re-watched Crimson Tide, and found ourselves on a self-imposed dive into a very particular rabbit hole…

If you’ve seen Crimson Tide, or the first few minutes of WarGames, you might already know what this post is about. Both films prominently make use of a one-time authentication device which the user snaps in half to reveal a card that has some secret code printed on it — and as it turns out, there are at least two different projects that aim to replicate the props used in the movies.

The props were inspired by the real-world “Sealed Authenticators” used by the United States to verify commands regarding the launch of nuclear weapons. As shown in the films, once a launch order, known as an Emergency Action Message, is received, its validity could be confirmed by breaking open one of the Authenticators and comparing the code sequence printed on it to what was sent along with the message. Supposedly the real ones are more like foil envelopes that would be torn open, but presumably that wasn’t cool enough for Hollywood.

So how do you make your own film-quality Authenticator? The two projects take slightly different approaches, but the basic idea is to create a three layer acrylic stack. The top and bottom pieces are identical, and scored in the middle so they’ll break along a clean line. The center piece is cut in half and largely hollowed out to create the compartment for your printed message. It’s perhaps best described as two “C” shapes that have slight gap where they meet, which provides some room for the top and bottom layers to flex. With the acrylic pieces aligned and the message inside, everything is solvent welded together.

Of course, the question now is what to do with them. We can think of all sorts of games and challenges that could make use of this kind of thing, but if you’re looking for something a little more practical, these would be an awesome way to store your two-factor authentication recovery codes. With the proper software, you could even use these for secure file storage via QR code.