0 sats \ 2 replies \ @moneroshill 30 Aug 2022 \ parent \ on: Bitcoin Physical Hardware Cash? bitcoin
Appears to be custodial unless the device stores a private key, thus defeating the purpose of bitcoin.
It does. Check the docs.
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I don't see any docs on that page, but there was an FAQ at the very bottom of the page describing a useless multisig setup:
No. The Bitcoin is accessible through a multisig loaded by the first holder of the note. One key of the multisig, the “user key”, is generated by the first holder and stored in plaintext on the note. The second key, a “manufacturer key” is generated at the time of manufacture and stored, encrypted on the note.
The multisig requires both keys to access funds until the “Claim Before” date printed on the note at which point in time the multisig downgrades so that only the user key can claim the funds. Under no circumstance can the manufacturer key claim funds alone.
What they are describing is basically a personal wallet with extra steps. You cannot use these notes as money because you have no way to prove that you don't remember the seed after you give the note to them.
In order to make bitcoin into physical money, you have to transparently make a computer chip the custodian of the bitcoin (such that the current owner can use it to sign transactions, but not the previous owner). See my comment here: #64833
There is also the example of the casascius' coin setup: a trusted party funds an address imprinted on the inside of the coin and revealing the private key destroys the coin: https://en.bitcoin.it/wiki/Casascius_physical_bitcoins
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