44.493 Issues in Criminal Justice Technology & Security

home > unit 9: biometrics and identification

Types of biometrics and technologies

• Digital Fingerprint recognition
  builds on long record of progress in fingerprint technology. Automates the process, extends it to general public:
  • Demo
  • Used for US-Visit program
    
• Hand Geometry
  • In one system, readers simultaneously analyze more than 31,000 points and instantaneously records more than 90 separate measurements of an individual's hand (including length, width, thickness and surface area)
  • Applications:
  • Workplace
    • Access
    • Time Recording
  • Differing technologies for low and high-volume access
    
• Facial Recognition
  • How it Works
  • Facial Recognition demo
  • Uses
    • Transactions
      
• Iris:
  • "The iris is much more unique than the fingerprint and is the most unique thing on the outside of the human body."
  • Iris ID at Heathrow Airport
    • Demo
  • Access Control
    • Demo
      
• Multibiometrics

• system developed at Carnegie-Mellon that integrates fingerprint, face and speech

Problems with Biometrics:

alleged Salem drug dealer burned his fingerprints off with acid

• Errors:
  • Usually measured in terms of 3 variables:
    • false accept rate (FAR) -- tned to be a high rate of false positives
    • false nonmatch or reject rate (FRR)
    • failure to enroll rate (FTE or FER).
  • "One of the most common measures of real-world biometric systems is the rate at the setting at which both accept and reject errors are equal: the equal error rate (EER), also known as the cross-over error rate (CER). The lower the EER or CER, the more accurate the system is considered to be."
  • Sensitivity to environmental conditions: "Samples taken in an airport are noisy in that the light is uneven, shadows can partially cover the face, the image may not be frontal, the subject may be wearing a disguise, and so on. These variations make matching more difficult."
  • Claimed error rates often flawed.
  • If they are keyed to "watch" lists, every time database size doubles, accuracy decreases by two to three percentage points overall (P.J. Phillips et al., Face Recognition Vendor Test 2002, National Institute of Standards and Technology, 2003).
  • Example: 38.6% error rate during facial recognition test at Logan
    
• Misuse
  potential problems include:
  • planting DNA at a crime scene
  • a criminal associating another's identity with his biometrics. This can mean that the criminal impersonates the innocent person without arousing suspicion
  • fool fingerprint detector by using piece of adhesive tape that has authentic fingerprint on it
  • show photo of someone else's iris to fool iris recognition camera.
  • interfere with the data interface between the device and the computer, so that "fail" gets changed to "pass."
    
• Threat to Civil Liberties
  • "..false positives must be investigated, which impinges on the privacy of innocent people."
  • "..degree of similarity between templates required for a positive match depends on a decision threshold, a user-defined system parameter. The user can specify high security, in which case innocent subjects might be caught when the system casts a broader net. Alternatively, the user might specify low security, in which case terrorists could escape. Setting this parameter thus directly affects the false positive rate, which in turn directly affects subjects' privacy."
  • "potential for biometric systems to locate and physically track airline passengers. People being scanned and possibly tracked may not be aware of the system and thus cannot control it. The US Constitution's Fourth Amendment guards against illegal searches and seizures by the government. Article 12 of the United Nations' Universal Declaration of Human Rights, adopted in 1948, guards against interference with privacy, family, or home. Thus, a case could be made that if a government agency installs and maintains a face-recognition system at an airport, data collected and used without a subject's consent could represent a civil liberties violation."

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