This Technical Specification specifies the logical characteristics and security features at the card/system interface for the European Citizen Card. The European Citizen Card is a smart card with Identification, Authentication and electronic Signature (IAS) services. Therefore: the supported services are specified; the supported data structures as well as the access to these structures are specified; the command set is defined. This Technical Specification aims to ensure the interoperability at card/system interface in the usage phase. In order to reach the interoperability objective, IAS services are compliant with EN 14890 Part 1 and Part 2. As the EN documents offer options, this specification fully defines a complete profile. This Technical Specification also considers ICAO Doc 9303. This Technical Specification does not mandate the use of a particular technology, and is intended to allow both native and Java card technologies. This specification encompasses mandatory and optional features. Optional features make up a toolbox of modular options from which issuers can pick up the necessary protocols to fulfil the requirements for use. Mandatory features shall be implemented for a smart card to be compliant with this Technical Specification. Mandatory features required for compliancy to ECC specification are given in Annex C, the optional features are given in Annex D. Two IAS-enabled smart cards issued by two different issuers, and compliant with this Technical Specification but implementing different application profiles out of this Technical Specification, can interoperate with a terminal provided that such a terminal supports both application profiles. Therefore, interoperability requires a specific agreement between issuers/governments in order to determine which cross-border services are to be shared, and consequently, which protocols are to be supported by the terminals in each country. All the APDU commands described in this Technical Specification are in accordance with ISO/IEC 7816 Part 4 or Part 8. They are fully described here in order to provide the settings adopted by this specification and to prevent any ambiguity in case of several possible interpretations of the standards. For physical, electrical and transport protocol characteristics, refer to CEN/TS 15480-1.