Overview
ISO/IEC 19794-7:2007 defines standardized biometric data interchange formats for dynamic handwritten signatures and sign time-series. The standard specifies two interoperable formats: a full format for general use and a compact format intended for constrained environments such as smart cards and tokens. Both formats support storing raw acquired signature samples (for feature extraction) and time-series features (for direct time-series comparison). ASN.1 specifications and encoding guidance are provided in an informative annex.
Key topics and technical requirements
- Data models and channels: Defines time-series channels such as X, Y, Z (pen position), VX/VY (velocity), AX/AY (acceleration), T/DT (time/time-difference), F (pen force), S (tip switch), and orientation channels (Az, El, TX, TY, R). X and Y are mandatory; either T or DT, or uniform sampling, must be indicated.
- Coordinate system & units: Uses a 3D Cartesian coordinate system (x right, y up, z perpendicular). Units and scaling (e.g., metres for position, m/s for velocity) are specified with integer encoding plus header scaling factors.
- Formats: Describes full and compact biometric data block (BDB) formats, including header/body organization and embedding in a CBEFF-compliant Biometric Information Record (BIR).
- Encoding & identifiers: Includes ASN.1 specifications (Annex B) and registered CBEFF format type identifiers for interoperability and integration.
- Conformance & best practices: Normative conformance rules for BDB structure and relations; Annex A offers best practices for data acquisition (sampling rate, device resolution, jitter measurement).
- Interoperability notes: Recommends encapsulation in CBEFF, and suggests time-stamping and cryptographic protection for authenticity (not within normative scope).
Applications and who uses it
ISO/IEC 19794-7 is applicable wherever dynamic signature biometrics are used:
- Biometric system and algorithm developers (feature extraction, time-series matching)
- Capture device and advanced pen system manufacturers
- Smart card / token vendors implementing the compact format
- System integrators for authentication, e-signature, access control, and transaction signing
- Standards bodies and certification labs implementing interoperable biometric exchange
- Forensic and identity-management professionals requiring standardized signature data interchange
Related standards
Keywords: ISO/IEC 19794-7, biometric data interchange, signature time series, dynamic signature, CBEFF, ASN.1, smart card compact format, biometric interoperability.
