Abstract: A method of executing a transaction on a smartcard of the type including a processor, a memory for storing a system program, an application programs and for storing data and an interface enabling communication with an external processor in a local terminal adapted to access related data is disclosed. The method comprises the steps of: determining from the data stored on the smartcard in a pre-transaction state if the transaction can be executed validly by the smartcard (102); determining from the related data stored in a pre-transaction state and accessible by said external processor if the transaction can be executed validly by the external processor (102); in response to said determining steps being affirmative, executing said transaction on said smartcard and by said external processor (105); and in response to said smartcard or said external processor failing to execute said transaction, restoring said data and said related data to the or each pre-transaction state (108).