In one aspect, a data processing device which comprises an application for use in an ad-hoc network whereby the application is provided with a data interface to a central service for the processing of the first data is provided. A proxy instance is connected to the application via a first data connection for the exchange of the first data, while the proxy instance is connected to a plurality of additional data processing devices via the ad-hoc network for the exchange of second data. The proxy instance is adapted to generate the first data from the second data and to generate the second data from the first data, the exchange of the first data between the application and the proxy instance being carried out via the data interface.