Secure Pin-managing a user trusted unit

The invention relates particularly to a method for a secure PIN management of user trusted unit (10) connected via a data processing means (15) comprises, the 'to a non-persistent memory (15 with a permanent memory (15)') and interfaces (17, 18, 20) for connecting or interaction with a user (1), a memory card (16) such. is connected as a smart card and a data station (30), said method comprising the steps of: providing with a memory card (16) connected to the unit; Received in the unit: an external PIN and a card PIN, the latter being able to unlock the memory card; Generating and storing a key in the persistent storage on the data processing means and from the received PINs, so that the card PIN may be calculated based on a function that is stored in the persistent memory, wherein the external PIN and the key as an argument become; Receiving a user input of the external PIN into the terminal and transmitting the PIN to the external unit; Instructing the data processing means to calculate the card PIN using the stored function; To unlock and use the calculated card PIN the memory card.