Checking an integrity of property data of a device by a tester

A method for checking an integrity of property data (ED1) of a device (100), wherein the characteristic data (ED1) include a program data set (PD1) and a set of configuration data (KD1) by a tester (300) within a network (400), which comprises device (100) includes the tester (300) and at least one further device (102) with another characteristic data (ED2), wherein said another characteristic data (ED2) has a further program data set (PD2) and a further set of configuration data (KD2) with the steps: - providing the property data (ED1) and said further feature data (ED2) through a station (200) which is coupled at least to the testing device (300) via the network (400); - evaluating the property data (ED1) and said further feature data (ED2) by the tester (300) to at least the identity of the program data set (PD1) and the further program data set (PD2), and assigning a label (Z) in dependence on a result of evaluating; to influence determination of a parameter (P, PC, PS1) which is adapted to a hash value (H1) and an audit hash value (H'1) of a hash function, by the testing device (300), - wherein the parameter (P, PC, PS1) is configured depending on the marking (Z), and transmitting said parameter (P, PC, PS1) to the device (100); - calculating the hash value (H1) through the device (100) as a function of the hash function and a character string, wherein the character string includes the parameters (P, PC, PS1) and the property data (ED1) and a sequence within the character string can be specified, and transmitting the hash value (H1) to the instrument (300); - calculating the audit hash value (H'1) by the tester (300) in response to the hash function and the character string, wherein the character string includes the parameters (P, PC, PS1) and the property data (ED1) and an order within the string can be predetermined; - confirming the integrity of the characteristic data (ED1) by the tester (300), if the hash value (H1) with the audit hash value (H'1) matches.