A method and a user device (1) for projecting a data file through a user device (1) are disclosed. The user device (1) has a reproducing device (1.7), means for identifying the user device (1) in a mobile radio network (5), and biometric recording means. The user is authenticated with the transmitted biometric data in a remote server (7) and downloads a data file to be projected or a key for decrypting a data file from the remote server (7) over the mobile radio network (5) in the user device (1). With the reproducing device (1.7) integrated in the user device (1), the data file or presentation is reproduced. The invention also concerns the disclosed user device (1).