The Quantum What? Advantage, Utopia or Threat?

International audienceQuantum computing is at the top of the agenda for several countries. They acknowledge the strategic importance of it. They invest significant public funds in the development of this technology. While some show unconditional enthusiasm, others are more moderate and even very critical with respect to the promises of quantum computing. It is not easy to navigate for a non-expert in the field. Does quantum computing have a real advantage or is it rather a utopia? Moreover, is quantum computing, as they say, a real threat to computer and Internet security? This article takes the point of view of non-experts and attempts to shed light on these questions. In turn, we consider quantum computing as an advantage, a utopia, or a security threat. We will briefly look at the applications that we think are the most promising. Then, we review the different efforts made by the participants engaged in the race for the quantum computer. Finally, we try to project ourselves into the future