Title: ""Gravitational attacks" on quantum cryptography"

It was thought that the unconditional security of quantum key distribution under the Bennett-Brassard protocol can be proven under the sole assumption that the known laws of physics are correct. In the talk I describe a practical attack procedure that, contrary to previous wisdom, cannot be proven to fail under the above assumption. The attack, if performed, can also be seen as an unconventional way to find experimental clues to quantum gravity.