Are offline payments possible without special equipment?

Question

Payment systems

Is it possible to create an electronic currency that can be used to pay without a network and without the possibility of its simple "copy" in principle? Are there any "magic" algorithms for implementing one-time transfers? I know that some bank cards and terminals can work offline, but this is all based on the impossibility of accessing the chip data and, as a result, it is synchronized with the server later anyway, and the idea of ​​​​introducing new devices similar to banking ones for the sake of such a scheme looks unpromising.

Answer 1

Technologically possible, but the question of trust arises...
...in fiat it is solved with a club, in crypt it is done with a distributed ledger. without access to which, alas
, such fiat is quite possible, because the magic of quantum cryptography can protect the physical connection between wallets...