Attempt 

The submission of a biometric sample to a biometric system for identification or verification. A biometric system may allow more than one attempt to identify or verify

AFIS 

Automated Fingerprint Identification System 

AFNOR 

Association Française de Normalisation 

BAC 

Basic Access Control  

BEM 

Biometric Evaluation Methodology 

BEM WG 

BEM Working Group

Biometrics*

Automated recognition of individuals based on their behavioural and biological characteristics 

BioAPI  

Biometrics Application Programming Interface standard 

Biometric data*

Biometric sample at any stage of processing, biometric reference, biometric feature or biometric property 

Biometric feature*

Numbers or labels extracted from biometric samples and used for comparison

Biometric identification application* 

System which contains an open-set or closed-set identification application 

Biometric reference* 

One or more stored biometric samples, biometric templates or biometric models attributed to a biometric data subject and used for comparison 

Biometric sample 

A biometric measure presented by the user and captured by the data collection system

Biometric system*

System for the purpose of the automated recognition of individuals based on their behavioural and biological characteristics 

Note that in CC evaluation terms, a biometric system may be a product or may be (part of) a system for evaluation

Biometric template*

Set of stored biometric features comparable directly to biometric features of a recognition biometric sample 

Biometric verification (application)* 

Application that shows true or false a claim about the similarity of biometric reference(s) and recognition biometric sample(s) by making a comparison(s) 

BIR* 

Biometric Information Record  

CBEFF 

Common Biometric Exchange File Format standard 

CC-BEM 

Common Criteria Biometric Evaluation Methodology

CEM 

Common Criteria Evaluation Methodology  

Closed-set identification*  

Application that ranks the biometric references in the enrolment database in order of decreasing similarity against a recognition biometric sample  

Common Criteria 

An international scheme for the security evaluation and certification of IT systems 

Comparison*

Estimation, calculation or measurement of similarity or dissimilarity between recognition biometric sample(s)/biometric features/biometric models and biometric reference(s) 

EAC 

Extended Access Control 

EAL 

Evaluation Assurance Level 

EDPS 

European Data Protection Supervisor 

Enrolee 

A user with a stored biometric reference template on file

Failure to acquire rate (FTA) 

The failure to acquire rate is the proportion of attempts for which a biometric system is unable to capture an image of sufficient quality. When a biometric system allows multiple attempts, FTA measures failure to capture over these multiple attempts

Failure to enrol rate (FTE) 

The failure to enrol rate is the proportion of the user population for whom the biometric system is unable to generate reference templates of sufficient quality. It is the equivalent of FTA for the enrolment process, and depends on the procedures used in enrolment (which may differ from the procedures for later identification). It includes those who, for physical or behavioural reasons, are unable to present the required biometric feature

False Acceptance 

An incorrect identification of an individual, or an incorrect verification of an impostor

False Accept Rate (FAR) 

The probability that a biometric system will incorrectly identify an individual, or will fail to reject an impostor. For a positive (verification) system, it can be estimated from:

(the number of false acceptances) ÷ (the number of impostor verification attempts) 

False Match Rate (FMR) 

The rate for incorrect positive matches by the matching algorithm for single template

comparison attempts. For a biometric system that uses just one attempt to decide acceptance, FMR is the same as FAR. When multiple attempts are combined in some manner to decide acceptance, FAR is more meaningful at the system level than FMR

False Non-Match Rate (FNMR) 

The rate for incorrect negative matches by the matching algorithm for single template comparison attempts. For a biometric system that uses just one attempt to decide acceptance, FNMR is the same as FRR. When multiple attempts are combined in some manner to decide acceptance, FRR is more meaningful at the system level than FNMR

False Rejection 

A failure to identify or verify a genuine enrolee

False Reject Rate (FRR) 

The probability that a biometric system will fail to identify a genuine enrolee. For a positive (verification) system, it can be estimated from:

(the number of false rejects) ÷ (the number of enrolee verification attempts) 

Impostor 

A person making a false claim about identity to the biometric system

ICTs 

Informaton and Communication Technologies 

Matching score 

A measure of similarity or dissimilarity between the biometric data and a stored template, used in the comparison process

Multimodal biometric 

A biometric device which uses information from different biometrics - e.g. fingerprint and hand shape; or fingerprints from two separate fingers. All statistical analysis of multimodal systems should consider how the modes are combined in the comparison process

Negative claim 

A claim by a user not to be enrolled in the biometric system. This may be needed to establish that double claims are not being made

MRTDs 

Machine Readable Travel Documents 

NIST 

National Institute of Standards and Technology 

One-to-many comparison*

Process in which a recognition biometric sample/biometric feature/biometric model set of one biometric data subject is compared against the biometric references of more than one biometric data subject to return a set of comparison scores 

One-to-one comparison*

Process in which a recognition biometric sample/biometric feature/biometric model set from one biometric data subject is compared to biometric reference(s) to produce a comparison score with respect to one biometric data subject, perhaps using additional data from the enrolment database 

Open-set identification*  

Application that determines a possible empty candidate list by collecting one or more biometric samples from a biometric capture subject and searching the enrolment database for similar biometric references

Positive claim 

A claim by a user to be enrolled in the biometric system. An explicit claim is often accompanied by a user identification, and may also be associated with a password or PIN.

PP 

Protection Profile. A form of generic Security Target defined in the Common Criteria

Receiver Operating Characteristics (ROC) 

A method of showing the performance of the biometric system over a range of decision criteria - usually shown as a graph that relates FAR to FRR as the decision threshold varies

ROC 

Receiver Operating Characteristics

ROC curve  

Receiver Operation Characteristic curve 

SOF 

Strength of Function 

Template ageing 

The gradual change of a user’s biometric feature(s) which requires periodic updating of the user’s reference template

Threat 

An intentional or unintentional potential event that could compromise the security integrity of the system 

Threshold 

A parametric value used to convert a matching score to a decision. A threshold change will usually change both FAR and FRR - as FAR decreases, FRR increases

UI  

User Interface 

UKBWG 

UK Biometric Working Group 

Vulnerability 

The potential for the function of a biometric system to be compromised by e.g. intention (fraudulent activity); design flaw (including usage error); accident; hardware failure; or external environmental condition