1 Authentication Technologies Authentication Mechanisms –Something you know –Something you have –Something you are Features –Authenticator & Base secret –Verifier –Verification Procedure

2 What you know Password/PIN –Authenticator & verifier –String comparison –Hashing? –Risks?

3 What you have Smart/Swipe cards Large base secret Risks? –Compared to Passwords?

4 What you are: Biometrics Identification: –Who are you? –Template/model comparison –“One-to-many” search –Choose most likely Verification –Is this you? –Template/model measure –“One-to-one” search –Thresholding

5 Subversion “As a general rule, if an authentification system is made by humans, it can be defeated by humans” Multifactor Authentication? Next: Risks & Attacks

6 Risks Masquerade Multiple Identities Identity Theft

7 Attacks Trial and Error –Passwords –Cards –Biometrics Replication Theft Digital Spoofing

8 Vulnerability Average attack space –Number of attacks to have 50% chance of succes False Acceptance Rate (FAR/FMR) –Percentage of successful attacks by imposter

9 Defences Trial and Error –Increase size of base secret –Limit guesses –Biometrics Tighten match criterion False Rejection Rate (FRR/FNMR) Replication –Liveness test? Theft –Add PINs or biometrics Digital Spoofing –Cryptography

10 Deployment Issues Enrolment –Establish the verifier –Security concerns? –Self-enrollment –Supervised enrolment Maintenance –Password aging Human memory! –Physical change Revocation

11 Operational Problems Forgetting Passwords –Cost of reset Loss or aging of devices Injury to biometric traits –Use redundancy

12 Economics Software Hardware Enrollment costs –Administrator –User Per-use cost Maintenance costs System downtime costs Revocation costs