A method and a system for secure transfer of an application from a server (S) into a reading device unit (2) with authentication of a user with a data carrier unit (1), the server (S) making available the application, wherein, between the data carrier unit (1) and the server (S), a first cryptographically secured channel (K1) is set up based on first cryptographic information (A), and between a security module (3) of the reading device unit (2) and the server (S) a second cryptographically secured channel (K2) is set up based on second cryptographic information (B). The application is transferred from the server to the reading device unit via the second cryptographically secured channel (K2).