WP1: Metrology for QKD implementation security This work-package aims to develop certifiable methods for the characterisation and the prevention of hardware vulnerabilities in practical QKD systems. Implementation security aims to study the vulnerabilities of QKD systems and to develop the most suitable techniques to remove them (Objective 1). Task 1.1: Metrology for detection efficiency-mismatch attack Task 1.2: Metrology for bright illumination attack Task 1.3: Metrology for back-flash attack