A method for reading at least one attribute stored in an ID token (106, 106'), wherein the ID token is assigned to a user, said method comprising the following steps: - authenticating the user to the ID token, - authenticating a first computer system to the ID token via a first network, - following successful authentication of the user and the first computer system to the ID token, enabling read access of the first computer system to the at least one attribute stored in the ID token, - transmitting the at least one attribute by means of end-to-end encryption from the ID token to the first computer system via the first network, - time stamping the at least one attribute by the first computer system, - signing the at least one attribute read from the ID token and the timestamp thereof by the first computer system, - transmitting the signed attribute and the signed timestamp from the first computer system to a second computer system via a second network, wherein the first network is a public network and the second network is a private network, wherein a firewall is arranged between the first network and the second network in order to protect the second network against unauthorised access, wherein the method comprises the following further steps: - sending a request from a third computer system to the second computer system, - specifying one or more attributes by the second computer system, - sending the attribute specification from the second computer system to the first computer system, wherein the read access of the first computer system is enabled in order to read the one or more attributes specified in the attribute specification from the ID token, wherein the third computer system has a plurality of predefined configuration datasets (158, 160,...), wherein each of the configuration datasets specifies a subset of the attributes, at least one data source, and a first computer system from a set of first computer systems (136, 136',...), wherein the attribute specification is transmitted from the second computer system firstly to the third computer system so that at least one of the configuration datasets which specifies a subset of the attributes containing the at least one attribute specified in the attribute specification is selected by means of the third computer system, and wherein the third computer system forwards the attribute specification to the first computer system specified in the selected configuration dataset, and wherein a connection is established via the third computer system between the first computer system specified in the selected configuration dataset and the ID token specified by the specification of the data source in the selected configuration dataset. - authenticating the user to the ID token, - authenticating a first computer system to the ID token via a first network, - following successful authentication of the user and the first computer system to the ID token, enabling read access of the first computer system to the at least one attribute stored in the ID token, - transmitting the at least one attribute by means of end-to-end encryption from the ID token to the first computer system via the first network, - time stamping the at least one attribute by the first computer system, - signing the at least one attribute read from the ID token and the timestamp thereof by the first computer system, - transmitting the signed attribute and the signed timestamp from the first computer system to a second computer system via a second network, - sending a request from a third computer system to the second computer system, - specifying one or more attributes by the second computer system, - sending the attribute specification from the second computer system to the first computer system,