Is anything like that, people is talking about here?
Well, there is one main requirement: it should require no external power supply. If there is power outage, that device should still work. Someone proposed chemical hashing, I thought more about mechanical hashing, because it seems to be easier to compute than using paper and pencil, and it should be easier to learn, how to operate that. I thought about something simple, like constructing some tables for basic operations, like addition, rotation, xor, then it could be possible to compute hash functions manually, just by rotating a crank, or providing needed energy to the system in other simple ways. For example, it could be possible to paint squares in different colours to represent zeroes and ones, then negating the whole number could be done by simply rotating some wheels inside it by 180 degrees.
I thought about many different ways of doing that, but it seems some mechanical engineer is needed to make it real. It could use some buttons, some magnets, some rotating wheels with hex digits from "0" to "f", there are many options. Each state can be represented in many different ways, you could also place something here, like a marble (when it is present, it could represent "logical one", and when it is empty, it could represent "logical zero"). It could use gravity to implement logical gates. I don't know exactly how to make it, because I didn't find anything like that anywhere, maybe just nobody needed it yet.
To put it simply, it should be better than paper and pencil, and should work in cases, where no electricity is available, or if there is power outage, that's the general idea behind it. And I think making it in a mechanical way would be the simplest solution to that, but maybe there is something better available, I don't know (but I am not convinced for example to the chemical solution, that could be hard to do in a typical home, I think building a physical machine, or passing a ready-to-assemble project for some manufacturer, would be easier).
Edit: some visualization, how it could look like:
https://upload.wikimedia.org/wikipedia/commons/4/44/Grant_mechanical_calculating_machine_1877.jpgOf course it is just an example, because hash functions are more complex than that.
Well, I don't even have all the knowledge present in memory to at least make a mental sketch of what would be needed. I am an electrical engineer but I am not even close to be able to put up something like this. This is something probably to be put up as a project with several stages an probably multiple teams working on each stage! Or someone really bright/smart/intelligent capable of pulling this off alone! I'm not that one for sure!
You need to know exactly about bits and bytes, cryptography, probabbly mechanical engineering, learn or find someone to design components in 3D software with great precision, think about probably thousands of details in each stage of the project etc.
If you are really into this, maybe we should start by making a statement and say: I have this goal. I want to do this and that. Whoever is interested and whoever has any type of skills, feel free to onbard. After that, we would need to start laying down the stages, tasks for each stage, what knowledge and skills are needed in each stage, etc. I can't see this done by simply throwing ideas in the air like we are doing!
If this machine is anything like the Turing machine, I can't imagine how many thousands of hours were spent by those 2 guys and probably by a bunch of other unknown people in the background!
Check this thing: Enigma machine used by Germans to encrypt messages
https://www.youtube.com/watch?v=G2_Q9FoD-oQxD
And then check the craking machine here, at aroun 5:30. Machine Turing built to decrypt Enigma machine encryption!
https://www.youtube.com/watch?v=Hb44bGY2KdU