INRiM – Istituto Nazionale di Ricerca Metrologica is the National Metrology Institute of Italy. INRiM is the project co-ordinator, and work-package leader for WP3. It participates in technical work-packages WP1, WP2 and WP3, based on its expertise in: developing traceable methods for characterising single-photon sources and detectors; generating, manipulating and characterising photonic quantum entanglement; cryogenic single-photon detectors and electronics.