memorize it. they can't steal that from you. prove me wrong?
You mean to memorize all those long private key, i think you must be joking.....
Ye this doesn't seem to be good solution. Hmm... physical private key, there is problem not how to store it, but where? There is no safe places from thieves, they know all people popular hiding places.
Best would be probably to hide in plain sight.
I remember a similar topic 2 years ago on BTCtalk or Reddit, basically a guy asked how to protect his paper wallet from thieves.
A user says that he should bury it on his lawn, he did it and said that he will dig it back in 10 years

So yea, either memorize it or bury it on your lawn, you will notice it right away when some meddling kids trying to dig on your lawn

memorize it. they can't steal that from you. prove me wrong?
You mean to memorize all those long private key, i think you must be joking.....
There's no way for human to be able to memorize private key, private key were made to be impossible for human to memorize.
Although, if he's using a wallet that uses seed, it can be easily memorized by making up a simple story