ah yeah you could I think do XOR by hand but I sure wouldn't want to.
I would think the easiest way to be purely manual is to just use a passphrase. it's easily memorizable, and it doesn't look like a seed phrase so you can hide it in multiple places, even pretty openly, as it doesn't on its own reveal or even imply anything.
You could also consider a "border wallet", which requires some digital prep like printing a paper, but I don't think it requires you to use a computer for calculations.
ah yeah you could I think do XOR by hand but I sure wouldn't want to.
I would think the easiest way to be purely manual is to just use a passphrase. it's easily memorizable, and it doesn't look like a seed phrase so you can hide it in multiple places, even pretty openly, as it doesn't on its own reveal or even imply anything.
You could also consider a "border wallet", which requires some digital prep like printing a paper, but I don't think it requires you to use a computer for calculations.