Introduction to Biometrics

1
Introduction to Biometrics

• Dr. Bhavani Thuraisingham
• The University of Texas at Dallas
• Lecture 23
• Biometrics Standards - II
• November 14, 2005

2
Outline

• BioAPI Standard
• Reference
• Chapter 17
• http//www.bioapi.org/DownloadsPage1.html

3
BioAPI

• This specification defines the Application
  Programming Interface and Service Provider
  Interface for a standard biometric technology
  interface.
• BioAPI V1.1 defines an open system standard API
  that allows software applications to communicate
  with a broad range of biometric technologies in a
  common way.
• As an open systems specification, the BioAPI is
  intended for use across a broad spectrum of
  computing environments to insure cross-platform
  support.
• BioAPI V1.1  was developed by the BioAPI
  Consortium and specifies standard functions and
  a biometric data format which is an instantiation
  of CBEFF.

4
BioAPI

• BioAPI creates a modular framework allowing
  programmers to develop once for a biometric
  device the easily make their work compatible with
  other devices
• Capabilities addressed by the API include
• Enrollment, verification, identification,
  capture, process, match, and store
• The goal is to hide as much as possible the
  unique aspects of individual biometric
  technologies and vendor implementations
• Attempts to provide a high level of abstraction
  that an be used within a number of potential
  software applications

5
BioAPI Specification, Version 1, March 2001

• Concepts
• BioAPI Definitions
• E.g., BioAPI data structures, Registry schema,
  Error handling, Framework operations, Streaming
  I/O, - - -
• BioAPI Service Provide Interface
• Data structures for the interface, service
  provider operations, Database operations

6
Concepts

• BSP Biometric Service provider
• BIR Biometric Identification Template
• API Model
• Client/Server Processing Methods
• Other Concepts

7
Biometric Service Provider (BSP)

8
Biometric Identification Record (BIR)
t
9
API Model

• There are three principal high-level abstraction
  functions in the API
• Enroll Samples are captured from a device,
  processed into a usable form from which a
  template is constructed, and returned to the
  application.
• Verify One or more samples are captured,
  processed into a usable form, and then matched
  against an input template. The results of the
  comparison are returned.
• Identify One or more samples are captured,
  processed into a usable form, and matched against
  a set of templates. A list is returned showing
  how close the samples compare against the top
  candidates in the set.

10
Supporting Client Server Processing Two
approaches

• Use Primitive Functions
• Capture, process, Match, Create Template
• Using streaming callback
• The client/server application decides whether the
  authentication should be driven by the client or
  the server component.
• The application calls the appropriate high-level
  function, and the BSP calls the Streaming
  Callback to initiate the BSP-to-BSP protocol.
• The StreamInputOutput function is used by the
  partner application to deliver messages to the
  partner BSP, and to obtain a return message to
  send to the driving BSP.

11
Primitive Functions
12
Using Streaming Callback Server Initiation
13
Using Streaming Callback Client Initiation
14
Other Concepts

• There are two possible criteria for the results
  of a match False Accept Rate (FAR) and False
  Reject Rate (FRR).
• FAR is the probability that samples falsely match
  the presented template,
• FRR is the probability that the samples are
  falsely rejected (i.e., should match, but dont).
  
• The BioAPI functions allow the application to
  request a match threshold in terms of maximum FAR
  value (i.e., a limit on the probability of a
  false match,) and an optional maximum FRR value.
  
• If both are provided, the application must tell
  the BSP which one should take precedence.

15
Other Concepts

• BIR Database The BioAPI allows a BSP to manage a
  database of BIRs
• To optimize the performance of the Identification
  operation over large populations
• To provide access to the BIRs that may be stored
  on a self-contained sensing device.
• User Interface Most biometric service providers
  come with a built-in user interface
• The API allows the application to control the
  look and feel of this user interface
• Module Registry Upon installation, BioAPI
  components (framework and BSPs) post information
  about themselves in the BioAPI module registry.
• This information is used by the application to
  determine if the BioAPI framework has been
  installed.

16
Example BioAPI API Definitions

• BioAPI_BIR A container for biometric data.
• typedef struct bioapi_bir
  BioAPI_BIR_HEADER
  Header BioAPI_BIR_BIOMETRIC_
  DATA_PTR BiometricData / length indicated in
  header /
  BioAPI_DATA_PTR Signature /
  NULL if no signature length is inherent in this
  type /
• BioAPI_BIR, BioAPI_BIR_PTR

17
Example BioAPI API Definitions

• A BSP schema entry as posted to the BioAPI module
  registry.
• typedef struct _bioapi_bsp_schema
• BioAPI_UUID ModuleId
• BioAPI_DEVICE_ID DeviceId
• BioAPI_STRING BSPName
• BioAPI_VERSION SpecVersion
• BioAPI_VERSION ProductVersion
• BioAPI_STRING Vendor
• BioAPI_BIR_BIOMETRIC_DATA_FORMAT
  BspSupportedFormats
• uint32 NumSupportedFormats
• uint32 FactorsMask
• uint32 Operations
• uint32 Options

18
Example BioAPI API Definitions

• A BSP schema entry (CONTINUED)
• uint32 PayloadPolicy
• uint32 MaxPayloadSize
• sint32 DefaultVerifyTimeout
• sint32 DefaultIdentifyTimeout
• sint32 DefaultCaptureTimeout
• sint32 DefaultEnrollTimeout
• uint32 MaxBspDbSize
• uint32 MaxIdentify
• BioAPI_STRING Description
• char Path
• BioAPI_BSP_SCHEMA, BioAPI_BSP_SCHEMA_PTR

19
Example BioAPI Service Provier Specifications

• BioSPI_ModuleEventHandler
• This defines the event handler interface that the
  BioAPI framework defines and implements to
  receive asynchronous notification of events of
  type BioAPI_MODULE_EVENT from a service provider
  module. Example events include insertion or
  removal of a hardware service module, or fault
  detection.
• typedef BioAPI_RETURN (BioSPI_ModuleEventHandler)
  (
• const BioAPI_UUID BSPUuid,
• void BioAPINotifyCallbackCtx,
• BioAPI_DEVICE_ID DeviceID,
• uint32 Reserved,
• BioAPI_MODULE_EVENT EventType)

20
Directions

• Development of the Standards
• Development of the Products
• Evaluation of the products
• What are the criteria used to evaluate the
  products?
• How do the products conform to the standards?
• Are there ratings?
• Is there a list of evaluated products
• Similar to the National Computer Security
  Center's list of evaluated securer system products