In this talk I will explain how some techniques coming from the local theory of Banach spaces can be used to obtain claims about the security of protocols for Position Based Cryptography. In particular, I will show how the knowledge about certain geometrical properties of particular Banach spaces (tensor norms on tensor products of Hilbert spaces) can be translated into lower bounds on the resources needed for cheating in this cryptographic task. I will finish pointing out some open problems and future directions suggested by our work. The contents of the talk are based on arXiv:2103.16357 (joint work with M. Junge, C. Palazuelos and D. Pérez-García).