Cryptocurrency was around ten years ago and has now become quite popular, cryptocurrency is designed by solving mathematical problems based on cryptography.
You can explain to the general public about this when playing with crypto / coin,
Interestingly, this can be done anytime and anywhere, not depending on the bank's work day or government work day, no downtime and transactions can be done in minutes.
Maybe this way you can explain so that you can quickly understand what is difficult to interpret. Hopefully success.