A removable device in the form of a key fob, adapted to connect to a head unit of a vehicle and comprising: a first communication module (320, 400) configured for bi-directional communication of data with the head unit; a second communication module (370, 400) configured for bi-directional communication of data with a wireless network (160, 262, 360), in particular a mobile telecommunication network; a memory unit storing an application programming interface, API (356, 545), implementing at least a first protocol for the communication with the head unit via the first communication module (320, 400); a control unit comprising at least one processing unit adapted to execute the API (356, 545); a biometric sensor, in particular a fingerprint scanner, for user identification; wherein the control unit is configured to perform an authentication process with the head unit via the first communication module (320, 400) and to perform encryption of the communication with the head unit in the application layer by running an application on the at least one processing unit; wherein the control unit is further configured to provide at least one service to the head unit via the first communication module (320, 400); wherein the control unit is further configured to provide a runtime environment for mobile apps; wherein the memory unit is further configured to store at least one mobile app, wherein the API (356, 545) further implements a set of routines and/or tools for the execution of the at least one mobile app on the at least one processing unit; and wherein the control unit is further configured to provide the at least one service to the head unit via the first communication module (320, 400) by executing the at least one mobile app in the runtime environment using the API (356, 545). a first communication module (320, 400) configured for bi-directional communication of data with the head unit; a second communication module (370, 400) configured for bi-directional communication of data with a wireless network (160, 262, 360), in particular a mobile telecommunication network; a memory unit storing an application programming interface, API (356, 545), implementing at least a first protocol for the communication with the head unit via the first communication module (320, 400); a control unit comprising at least one processing unit adapted to execute the API (356, 545); a biometric sensor, in particular a fingerprint scanner, for user identification; wherein the control unit is configured to perform an authentication process with the head unit via the first communication module (320, 400) and to perform encryption of the communication with the head unit in the application layer by running an application on the at least one processing unit; wherein the control unit is further configured to provide at least one service to the head unit via the first communication module (320, 400); wherein the control unit is further configured to provide a runtime environment for mobile apps; wherein the memory unit is further configured to store at least one mobile app, wherein the API (356, 545) further implements a set of routines and/or tools for the execution of the at least one mobile app on the at least one processing unit; and wherein the control unit is further configured to provide the at least one service to the head unit via the first communication module (320, 400) by executing the at least one mobile app in the runtime environment using the API (356, 545).