CBEFF Data Elements

CBEFF Fields


CBEFF data elements are placed in “fields” within a CBEFF file. The fields are grouped in three major sections:  

Standard Biometric Header (SBH)

Biometric Specific Memory Block (BSMB) 

Signature Block (SB)

Standard Biometric Header (SBH)

The Standard Biometric Header includes a series of required or optional fields as indicated below:

For a copy of a Table describing the SBH fields followed by the BSMB and the SB, please click here  (8KB - pdf file)

Definitions and suggested values for each of the fields are specified in NISTIR 6529. The fields do not need to be included if they are optional. CBEFF requirements do not include utilizing the exact values defined in the NISTIR, however the use of these values is strongly recommended. Translation between different formats will be facilitated if these values are used.  If the specification or standard that meets CBEFF requirements changes, these values then must be properly documented. (An attempt has been made in NISTIR 6529 to match the suggested field values to the current BioAPI v1.0 specification to simplify translation from CBEFF to BioAPI.)  
 

Biometric Specific Memory Block

This block contains the biometric data. It is simply a block of memory that can be specified in any way by the owner of the type as specified in the Format Owner/Format Type field of the SBH. Therefore, this can be a proprietary format or one agreed upon by a Standards Body, Working Group, or Industry Consortium. 

The Vendor, Standards Body, Working Group, or Industry Consortium can place a biometric template directly into this field, or it can specify a format for the data with further parameters, information, and data. 

The BSMB field format (e.g., a single bit map image) may not need any specification. There is likely to be a format analogous to the header/data format of most data storage structures. In this way, a vendor who "owns" this format can specify information in a header including version information, etc. Furthermore, it is conceivable, or likely, that Standards Bodies, Working Groups, or Industry Consortiums may agree upon common standard formats within BSMBs. 

The BSMB may contain the following information:

          (1) BSMB Subheader - may contain such information as version number, length of data, encryption info, etc. 

          (2) BSMB data - block of memory containing biometric data
 

The BSMB may contain raw, intermediate, or processed biometric data collected for purposes of immediate matching or enrollment. The BSMB may include one or more samples of biometric data as well as non-biometric data.

Signature

This field holds the Signature or MAC data. This field can contain Algorithm Identifier information and/or any parameters needed to perform the Signature and/or the MAC function. This field exists only if the CBEFF Integrity Options field is 0x01 or 0x02.

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