Combination of Paper, MOF and AI can provide ultra military grade protection

[Synchronice]

This is for educational purposes since these methods will be very hard to follow for average person but I find this information very interesting and I think you'll feel this way too. That's why I want to share it with you.

Chinese professor and his colleagues discovered this method during a failed experiment. Long story short, they printed text and patterns on paper with MOF ink. When they sprayed n-Butanol & Methylammonium bromide mixture, images become visible in some minutes.
In this experiment, they used a non-luminescent MOF that isn't exposed to UV lights. Instead, it exposes to UV once it gets converted from a MOF to perovskite nanocrystals. MOF precursors for ink are easy and cheap and information stored by the MOF ink is stable. While the Pb in lead halide is toxic, they already successfully replaced it with non-toxic tin. I know this line is hard to understand but I think this news means that in future paper wallet fans may have advanced ink for further protection.
^{[Source 1]}, ^{[Source 2]}

But now, here comes a role of artificial intelligence that makes this method even deadlier. In this experiment, they used Carbon nanoparticles unlike non-luminescent MOF which is superior in this case.

This is a brief quote: Advances in artificial intelligence can ensure that messages are only decipherable on properly trained computers. So, Weiwei Zhao, Kang Li, Jie Xu and colleagues wanted to train an AI model to identify and decrypt symbols printed in a fluorescent carbon nanoparticle ink, revealing hidden messages when exposed to UV light. They taught an AI model, composed of multiple algorithms, to recognize symbols illuminated by UV light and decode them using a special codebook. Finally, they tested the AI model’s ability to decode messages printed using a combination of both regular red ink and the UV fluorescent ink. With 100% accuracy, the AI model read the regular ink symbols as “STOP”, but when a UV light was shown on the writing, the invisible ink illustrated the desired message “BEGIN”. Because these algorithms can notice minute modifications in symbols, this approach has the potential to encrypt messages securely using hundreds of different unpredictable symbols, the researchers say.^{[Source 3]}


It's late evening and somehow my mind was thinking about creative & secure methods for paper wallet 

[jackg]

It's possible to do something like this for a paper wallet but there might be limits to it's security unless the "secret code serifs" had general ways to decode them and could be encrypted with other ink that can be read in a different way. It feels a lot like the idea of printing something and hiding words in what you've printed by making them tiny in the words you're printing.

I think a lot of people would have concerns their data is backed up correctly in this case too. It's an interesting way to provide a backup if there's other methods you can restore from that are less prone to being damaged.

[odolvlobo]

Invisible ink is only useful if the attacker doesn't know it is there and doesn't consider looking for it, or doesn't have the means to reveal it.

[ABCbits]

I briefly skimmed all source you mentioned, but apparently there's no mention how long material of this invisible ink could last. It would be nightmare to try recover your paper wallet, but found out the invisible ink is partially or fully gone which makes recovery impossible.

Invisible ink is only useful if the attacker doesn't know it is there and doesn't consider looking for it, or doesn't have the means to reveal it.

And third source mentioned by OP mention the invisible ink can be revealed with UV light which is easy to obtain.

[NotATether]

I don't think the AI part will be very secure, because AI by definition must be trained by humans in order to not make mistakes. It might as well be broken by the humans themselves using specialized but "dumb" algorithms.

[Synchronice]

I briefly skimmed all source you mentioned, but apparently there's no mention how long material of this invisible ink could last. It would be nightmare to try recover your paper wallet, but found out the invisible ink is partially or fully gone which makes recovery impossible.

It's mentioned that MOF inks are very stable. Definitely we don't know the duration but since this kind of discoveries are mostly done for securely encrypting the data, I'll remain positive and hope it's no different from traditional ink in terms of stability.

Invisible ink is only useful if the attacker doesn't know it is there and doesn't consider looking for it, or doesn't have the means to reveal it.

And third source mentioned by OP mention the invisible ink can be revealed with UV light which is easy to obtain.

Third source hasn't used non-luminescent MOFs. Instead, they used traditional ink that's only visible in UV light. If we change that ink with non-luminescent MOFs, then we will get enhanced security because I don't think it's easy to find halide salt that's necessary for making non-luminescent MOFs visible. Definitely this method is way better in terms of security than traditional invisible ink that gets revealed under UV lights. That's why I united two topics.