A smart card contains potentially multiple applications, each containing an application identifier (AID). Each application also incorporates an AID interpreter for providing access to the AID. This is achieved by making a request to the AID interpreter to provide the AID for the application. In response, the AID interpreter retrieves a first component of the AID. This first component is logically internal to the AID interpreter. The AID interpreter also retrieves a second component of the AID. This second component is logically external to the AID interpreter and is indicative of a state relevant to the application, such as a current balance in the card. The first and second components of the AID are then combined in order to generate the AID for providing in response to the request.