Smart card with a processor and a non-volatile storage medium, wherein the smart card is configured such that applications which are installed on the storage medium and which do not belong to the same security domain (SD1-SD5, SD8) are isolated from one another, wherein at least the following are installed on the storage medium: - a persistence application, which is assigned to a first security domain and is protected from being accessed by any application that is external to the smart card, wherein the persistence application is protected from being accessed by any application that is external to the smart card in that it is free from an APDU interface (Al), wherein the persistence application includes a program logic for storing data on the storage medium and for reading the stored data, wherein the persistence application comprises exclusively a program logic for storing the data on the storage medium, for reading the stored data from the storage medium and for exchanging data via a further interface with a main application, - the main application, which is assigned to the first security domain and includes an interface (Al) to an application that is external to the smart card and a further interface for exchanging the data with the persistence application, wherein the main application includes a program logic for processing the data, which program logic is configured such that already processed data are transmitted to the persistence application via the further interface in order to be stored on the storage medium, and data to be processed are received from the persistence application via the further interface, wherein the main application comprises exclusively a program logic for exchanging data with the external application and/or with further external applications, for exchanging the data with the persistence application and/or for processing the data. - a persistence application, which is assigned to a first security domain and is protected from being accessed by any application that is external to the smart card, wherein the persistence application is protected from being accessed by any application that is external to the smart card in that it is free from an APDU interface (Al), wherein the persistence application includes a program logic for storing data on the storage medium and for reading the stored data, wherein the persistence application comprises exclusively a program logic for storing the data on the storage medium, for reading the stored data from the storage medium and for exchanging data via a further interface with a main application, - the main application, which is assigned to the first security domain and includes an interface (Al) to an application that is external to the smart card and a further interface for exchanging the data with the persistence application, wherein the main application includes a program logic for processing the data, which program logic is configured such that already processed data are transmitted to the persistence application via the further interface in order to be stored on the storage medium, and data to be processed are received from the persistence application via the further interface, wherein the main application comprises exclusively a program logic for exchanging data with the external application and/or with further external applications, for exchanging the data with the persistence application and/or for processing the data.