1. Keystroke Biometric Studies
Assignment 2 – Review of the Literature Case Study – Keystroke Biometric
Describe problem investigated (intro + abstract)
Developed keystroke biometric system for long-text input, identification/authentication performance, two independent variables – keyboard type/input mode, longitudinal studies
Build case for usefulness of the study (introduction)
How the study will advance understanding
Explain why the study should be conducted
Evaluate, organize, and synthesize literature
Keystroke Biometric Studies

2. A Keystroke Biometric System for Long-Text Input
Journal article
Int. Journal of Information Security and Privacy
Authors
Charles C. Tappert, Sung-Hyuk Cha, Mary Villani, and Robert S. Zack
Summarizes keystroke biometric work
3 DPS dissertations
2 on identification, 1 on missing/incomplete data
About 12 masters-level projects
New material – authentication, longitudinal, touch-type model
Keystroke Biometric Studies

3. Build a Case for Usefulness of Study (9 paragraphs of introduction)
Validate importance of study – applications
Define keystroke biometric
Appeal of keystroke over other biometrics
Previous work on the keystroke biometric
No direct study comparisons on same data
Feature measurements
Make case for using: data over the internet, long text input, free (arbitrary) text input
Extends previous work by authors
Summary of paper organization
Keystroke Biometric Studies

4. 1) Validate importance of study – describe important applications
Internet authentication application
Authenticate (verify) student test-takers
Internet identification application
Identify perpetrators of inappropriate
Internet security for other applications
Important as more businesses move toward
e-commerce
Keystroke Biometric Studies

5. 2) Define Keystroke Biometric
The keystroke biometric is one of the less-studied behavioral biometrics
Based on the idea that typing patterns are unique to individuals and difficult to duplicate
Keystroke Biometric Studies

6. 3) Appeal of Keystroke over other Biometrics
Not intrusive – data captured as users type
Users type frequently for business/pleasure
Inexpensive – keyboards are common
No special equipment necessary
Can continue to check ID with keystrokes after initial authentication
As users continue to type
Keystroke Biometric Studies

7. 4) Previous Work on the Keystroke Biometric
Identification versus authentication
Most studies were on authentication
Few on identification (more difficult problem)
Short versus long text input
Most studies used short input – passwords, names
Two commercial products on hardening passwords
Few used long text input – copy or free text
Other keystroke problems studied
One study detected fatigue, stress, etc.
Another detected ID change via monitoring
Keystroke Biometric Studies

8. 5) No Direct Study Comparisons on Same Data
No comparisons on a standard data set
(desirable, available for many biometric and pattern recognition problems)
Rather, researchers collect their own data
Nevertheless, literature optimistic of keystroke biometric potential for security
Keystroke Biometric Studies

9. 6) Feature Measurements
Features derived from raw data
Key press times and key release times
Each keystroke provides small amount of data
Data varies from different keyboards, different conditions, and different entered texts
Using long text input allows
Use of good (statistical) feature measurements
Generalization over keyboards, conditions, etc.
Keystroke Biometric Studies

10. Keystroke Biometric Studies
7) Make Case for Using
Data over the internet
Required by applications
Long text input
More and better features
Higher accuracy
Free text input
Predefined copy texts unacceptable
Keystroke Biometric Studies

11. 8) Extends Authors Previous Work
Identification feasibility: fixed text & same keyboard for train/test
Improved identification system – two independent variables
Ideal: same input mode & keyboard type for train/test
Non-ideal: different input mode and/or keyboard type for train/test
Authentication system and associated studies
Ideal and non-ideal conditions as above
Longitudinal (over time) identification & authentication studies
Hierarchical feature/fallback model and parameter studies
New work
Further clarifies presentation + improved results
Obtained Receiver Operating Characteristic (ROC) curves
from k-nearest-neighbor classification procedure
Keystroke Biometric Studies

12. 9) Summary of Paper Organization
Introduction (described above)
System components
Data capture over internet
Feature extraction
Classification – identification and authentication
ROC curve derivation – two methods
Experimental design and data collection
Experimental results
Identification
Authentication – including ROC curves
Longitudinal studies
System model and parameters
Conclusion and future work
Keystroke Biometric Studies

13. Build a Case for Usefulness of Study (9 paragraphs of introduction)
Validate importance of study – applications
Define keystroke biometric
Appeal of keystroke over other biometrics
Previous work on the keystroke biometric
No direct study comparisons on same data
Feature measurements
Make case for using: data over the internet, long text input, free (arbitrary) text input
Extends previous work by authors
Summary of paper organization
Keystroke Biometric Studies

14. No Explicit Research Question or Hypotheses
Implicit research question
What identification and authentication performance (accuracy) can be attained by a long-text-input keystroke biometric system and how does performance vary over various controlled changes
Implicit research hypotheses
Performance decreases
In going from ideal to non-ideal conditions
As time between enrollment and testing increases
As the input text length decreases
Keystroke Biometric Studies

15. Keystroke Biometric Studies
Summary
Describe problem investigated (intro + abstract)
Developed keystroke biometric system for long-text input, identification/authentication performance, two independent variables – keyboard type/input mode, longitudinal studies
Build case for usefulness of the study (introduction)
How the study will advance understanding
Explain why the study should be conducted
Evaluate, organize, and synthesize literature
Keystroke Biometric Studies