Double spend isn’t like printing money on a printer.
It’s more like being able to write two checks for your whole bank balance
and having them both clear.
So very relevant are:
- whatever goods you bought with the checks need to be impossible to recall. So, like you need to find (two) someone’s who will effectively cash your check. You can’t buy a house because the police will come take the house back.
- you need to do it fast. The second you make are the first transaction you need fork and start mining hard. 51% gives you a speed advantage, but it’s very small. It still takes time to get the network to follow you.
Double spend is a very specific heist. Even if someone did it, it wouldn’t mean Bitcoin is valueless, it would just mean a certain class of heist is somewhat more probably and people need to adjust their security practices accordingly.
Tricks like waiting for extra confirmations, requiring identification before accepting payment, etc, are easy remediations.
It’s more like being able to write two checks for your whole bank balance and having them both clear.
So very relevant are:
- whatever goods you bought with the checks need to be impossible to recall. So, like you need to find (two) someone’s who will effectively cash your check. You can’t buy a house because the police will come take the house back.
- you need to do it fast. The second you make are the first transaction you need fork and start mining hard. 51% gives you a speed advantage, but it’s very small. It still takes time to get the network to follow you.
Double spend is a very specific heist. Even if someone did it, it wouldn’t mean Bitcoin is valueless, it would just mean a certain class of heist is somewhat more probably and people need to adjust their security practices accordingly.
Tricks like waiting for extra confirmations, requiring identification before accepting payment, etc, are easy remediations.