This part of ISO/IEC7816 specifies a registration procedure for application providers, and establishes the authorities and procedures to ensure and optimize the reliability of this registration. NOTE 1 ISO/IEC 7816-4 defines the structures of registered application provider identifiers (RIDs), and how to use them. A registered application provider identifier (RID) consists of five bytes. NOTE 2 In international RIDs (assigned by the international registration authority), the first quartet is set to 'A'. NOTE 3 In national RIDs (assigned by a national Registration Authority), the first quartet is set to 'D' and a relevant country code follows (see Annex B).