Practical treatment of quantum bugs

A quantum bug, or "qbug", is the fundamental unit of problems in quantum key distribution. It can include a particular attack, an inaccurate use of the technology, a loophole of the theory or a hidden side channel. In this manuscript we detail one of them, related to the choice of the protocol and its security proof in the finite-size scenario. The treatment makes use of linear programming, a tool that well adapts to the practical constraints imposed by an actual quantum key distribution set up.