Abstract: The present invention relates to a mobile, portable and compact signature device which is used for simple and secure signature of information by a user. In particular the device is protected from manipulation attempts by the combination of two measures: firstly the architecture ensures that information can only be shown on the display and signed when decrypted by the Smartcard in the device and thus intended for a specific user identity represented by the Smartcard. Secondly further manipulation opportunities for a potential attacker are restricted by the permanent combination in everyday use of the signature device with display and Smartcard. The area of application of the signature device disclosed and associated method includes but is not restricted to the authorisation of financial transactions.