The present invention relates to a method to access a data store previously locked using a passphrase from a device. The method includes the following steps, when the user requests access to the data store: requesting the user to enter the personal code; generating an access code by applying a first function to at least the entered personal code; sending out, to the server, at least an identifier of the device and the access code; for the server, comparing the access code with the preliminary received first function; for the server, if the access code is correct, returning the passphrase to the device; and for the device, unlocking the data store using the received passphrase in combination with the entered personal code.