I can imagine that, in the near future, there will be headstones in cemeteries, with nothing on them except a QR code, which will require an app to scan, and a

I can imagine that, in the near future, there will be headstones in cemeteries, with nothing on them except a QR code, which will require an app to scan, and a key to decrypt the data. I wonder what future civilisations - where smartphones and encryption algorithms have been long lost - will make of that? And we thought the Egyptians left us a tough one to crack!