Abstract: Nonlocal games are a foundational tool in quantum information and complexity. They give an operational perspective on entanglement, which in turn has led to many protocols in settings with multiple spatially-separated quantum devices. A recent line of work initiated by Kalai et al (STOC’23) investigates to which extent spatial separation can be replaced by timelike separation, by using cryptography. I will give a gentle introduction to this topic and its motivations and discuss a recent result that characterizes the well-known class of “XOR games” in this setting. This resolves an open question and establishes a computational version of Tsirelson’s theorem. Based on https://arxiv.org/abs/2402.17301.