The invention is directed to a process for the recovery of sulphuric acid from a mixture comprising sulphuric acid and hydrocarbons, in particular carbohydrates. The management device generates and transmits a TRL formed from data that expresses terminal IDs of all terminals to be invalidated, by only a value and a position of a common bit string in the IDs, to the content key distribution device. With the proposed solution, it is possible in particular to examine lithography masks for defects by means of inspection microscopes in spite of increasingly smaller structures and increasingly higher image-side numerical apertures of the imaging systems.