A method is provided for cryptographic protection of an application associated with an application owner and executed in an external data processing center having a security module that stores private cryptographic material of the application owner. A first secure channel between the security module and application owner and a second secure channel between the application owner and the application are used for transmitting a cryptographic key. The cryptographic key is automatically made available to the secure module and the application via the secure channels, without the data processing center service operator being able to access said key. The application can authenticate itself using the key so that the cryptographic material can be transmitted to the application via a channel protected by the cryptographic key. The application data can be encrypted using the cryptographic material such that the application data cannot be accessed by the data processing center service operator.