Is it possible to create an electronic currency which you can pay without a network and without the possibility of its simple "copy" in principle? Are there any "magic" algorithms to implement single transfers? I know that some Bank cards and terminals can work offline, but it all rests on the inability to access the data of the chip and in the end it's still later synchronizes with the server, and the idea of the introduction of new devices of the same Bank for such schemes looks bleak.