ISO/IEC 39794-1:2019

Overview - ISO/IEC 39794-1:2019 (Extensible biometric data interchange formats - Framework)

ISO/IEC 39794-1:2019 defines a framework for extensible biometric data interchange formats designed so new data elements can be added without invalidating existing data structures. It specifies the meaning of common data elements, common data structures for both tagged binary (ASN.1) and textual (XML Schema) encodings, and introduces conformance testing concepts to verify syntactic correctness of biometric data blocks (BDBs). The standard was prepared by ISO/IEC JTC 1/SC 37 (Biometrics).

Key technical topics and requirements

• Extensibility rules and guidelines - how to design formats that can evolve while remaining backward compatible.
• Common data elements - standardized abstract elements such as version, representation, capture device, capture date/time, quality metrics and PAD (Presentation Attack Detection) data.
• Abstract data structures - definitions of version blocks, representation blocks, and extended data blocks to ensure consistent interpretation.
• Encoding schemes - support for two encodings:
  • Tagged binary using ASN.1 for compact machine-readable BDBs.
  • XML Schema definitions for textual interchange and human-readable representations.
• Naming and identification conventions - for ASN.1 modules, XML namespaces and resource identifiers used across the ISO/IEC 39794 series.
• Conformance testing methodology - concepts and procedures for syntactic conformance testing of biometric data blocks, enabling interoperable implementations.
• Guidance on capture and quality - rules for capture date/time, degree of processing (captured sample, intermediate sample, feature set), capture conditions, device requirements and quality requirements for biometric data.

Practical applications and who uses this standard

ISO/IEC 39794-1:2019 is intended for organizations and professionals who design, implement or evaluate biometric systems and data exchange flows, including:

• Biometric device and sensor manufacturers (capture devices)
• Biometric software developers and integrators (feature extraction, matching, storage)
• Identity management, border control and law-enforcement agencies deploying interoperable biometric exchange
• Test laboratories and certification bodies performing conformance testing
• Standards architects and implementers using ASN.1 and XML Schema to create interoperable biometric message formats

Using this framework helps ensure reliable data interchange, backward compatibility when formats evolve, and consistent handling of metadata such as quality and capture conditions - all critical for scalable, interoperable biometric ecosystems.

Related standards and references

• ISO/IEC 19794 series (historical biometric interchange formats)
• CBEFF (Common Biometric Exchange Formats Framework) - referenced for relationships and identifiers
• ASN.1 and XML Schema technologies for encoding and schema design

Keywords: ISO/IEC 39794-1:2019, biometric data interchange formats, extensible, ASN.1, XML Schema, tagged binary, conformance testing, biometric quality, capture device, BDB.