2. QKD and cryptography issues

Quantum Key Distribution is complex in theory and practice. The applied principles of quantum physics are arduous, as they are sometimes counter-intuitive in nature. A good overall understanding of QKD systems remains difficult without knowledge of mathematical concepts (Hilbert space, Dirac, tensor product, information and communication theory) and underlying quantum physics concepts (superposition of state of all continuous measurable values, decoherence, indeterminacy of these measurable values in a superposed state but following known probability laws, taking of precise extrema -dichotomous- values during measurement, entanglement of particles synchronizing measured values even when physically separated, modeling of the quantum state by a wave function with complex amplitudes – not correctly interpretable in the real world –, no-cloning – impossibility of copying qubits –, etc.). The...