ISO/IEC 19785-3:2007 specifies several patron formats that conform to the requirements of ISO/IEC 19785-1.
ISO/IEC 19785-1 defines a basic structure for standardized biometric information records (BIRs) that consists of three parts, the standard biometric header (SBH), the biometric data block (BDB), and the security block (SB). CBEFF also defines several data elements and their standardized abstract values that can be used in SBHs and SBs (CBEFF treats the BDB as opaque data). CBEFF also establishes mechanisms by which organizations, called "patrons" by CBEFF, can specify and publish BIR format specifications, which are in turn called "patron formats". CBEFF enables patrons to develop BIR specifications that are fully standardized and interoperable, yet are specifically adapted to the requirements of a particular application environment.
CBEFF defines rules for BIRs that contain only one BDB (simple BIR) and that contain at least one BDB (complex BIR). CBEFF defines mandatory data elements that identify the format of a BDB and its security attributes (encryption and integrity). All the other CBEFF-defined data elements and abstract values are optional. CBEFF enables patrons to define additional data elements and abstract values as required by the application environment