Biometric Authentication in a Wireless Environment

1. Biometric Authentication in a Wireless Environment Alex Kotlarchyk Florida Atlantic University

2. Goals • Biometric protocols suitable for a wireless networked environment • Secure system/network access via biometric authentication • Secure wireless transmission of biometric data

3. Why Wireless Biometrics? • Combination of two rapidly growing technologies • Biometric systems for verification and identification • Homeland Security • Wireless systems for mobility • Over 1 trillion wireless phone min. in US, 2004 • Common advantage is convenience

4. Current Examples of Biometric Deployments • Eastern Financial’s Boca Mission Bay branch • Handprint scan to unlock the door to safe deposit boxes • Statue of Liberty • Fingerprint scan to access lockers • Nine Zero hotel in Boston • Iris scan for entrance to $3,000-a-night suite • Piggly-Wiggly grocery stores • Testing pay-by-fingerprint system • Bank of Tokyo-Mitsubishi • Credit cards w/ embedded vein-pattern information

5. Human authentication • Types of human authentication • What you know (secret) • Password, PIN, mother’s maiden name • What you have (token) • ATM card, smart card • What you are (biometric) • Stable: fingerprint, face, iris • Alterable: voice, keystroke • Where you are (authorization?) • Wireless

6. Suitability of Biometrics • Paradox of secure biometrics • A biometric is stable and distinctive. This is good for identification. • However, something unique can never be changed. This is not so good for verification if the biometric is compromised. • Furthermore, a biometric is not a secret, so it can be found and copied. This is bad. • So, are stability and uniqueness not good after all?

7. Keyspace • Number of possible codewords (CW) • Token • 12-digit: CW = 10^12 CWs • Password • Full 62 ASCII alphanumeric chars used randomly in an 8-char password = over 10^14 CWs • Most actual users selection ≈ 10^6 CWs, so in practice, the 12-digit token is more secure • Biometrics (2001 technology, may change) • ≈ inverse of FAR • Iris ≈ 10^6 CWs • Fingerprint ≈ 10^4 CWs • Voice ≈ 10^3 CWs • Face ≈ 10 → 100 CWs

8. Increasing Keyspace • Combined authentication to increase keyspace • Multibiometric authentication • More than one biometric • Combine standard biometrics (e.g. face and fingerprint (multimodal), or multiple fingerprints) • Combine standard biometric with “soft” biometric • Soft biometric = gender, height, race, eye color, etc. • Multifactor authentication • More than one authentication type • Combine biometric w/ password or token

9. Source: Technology Review, June 2004

10. Biometric Advantages • Convenience • Can’t be lost (in general) • Can’t be forgotten • Can’t be loaned • Mostly unique (matching may not be) • Perceived strong non-repudiation • Does not change significantly (in general) (Ident.) • Both verification and identification applications

11. Biometric Disadvantages • Ability to authenticate dependent on technology (FAR, FRR) • Personal data, but not secret/secured data • Easy to copy raw data • Cost of technology • Non-revocable • Cannot change if compromised (Ver.) • Inexact matching (variable presentation) • Social acceptance

12. Biometric Authentication System Source: Podio, NIST

13. Template Size

14. Wireless Biometric System Security • Security issues • Biometric authentication to ensure secure access to the system/network • In other words, wireless system access security • Wireless message authentication to ensure secure transmission of biometric data • In other words, personal information security and privacy across the wireless network • Physical security • Devices, computers, transmitters/receivers, etc.

15. Biometric Authentication Threats

16. Defense of Biometric System • Capture device presented with ‘false’ biometric • e.g. fake finger, short video, high-res color iris image, latent image • Use biometric ‘in addition’ not ‘instead of’ (multi-verification) • Vitality sensor, 3-D confirmation

17. Defense of Biometric System (continued) • Modification of capture device • Only a problem if capture and template generation (and maybe matching) are done on the device (trusted biometric device) • Tightly integrate capture mechanism with processing hardware • Ruggedize device • Display physical sign of tampering • Inactivate if tampered (TILT!) • Encryption of template

18. Defense of Biometric System (continued) • Remainder are network security or template database security issues • Wireless network security will be discussed • Database security is beyond the scope of this presentation • Don’t forget OS security

19. Biometric Cryptography • Use of biometric data for encryption & decryption • “fuzzy” commitment, vault – Ari Juels, RSA Labs

20. Biometric Cryptography (example) 01010 10101 00000 11111 01010 01010 Enroll (Encrypt) Password (hashed) Template (key) E(h(Pwd)) “stored” compare Within Threshold? Template (key) 10000 10111 “live” Hamming Distance = 2 11010 11101 Verify (Decrypt)

21. Biometrics Standards • Common Biometric Exchange File Format (CBEFF) • ANSI-NIST-ITL-2000 • Data exchange & quality • Criminal identification • American Association for Motor Vehicle Administration (AAMVA) DL/ID 2000 • FBI • Wavelet Scalar Quantization (WSQ) – fingerprint image (de)compression • Electronic Fingerprint Transmission Standard (EFTS) • Intel Common Data Security Architecture (CDSA) • ANSI X9.84 – Biometric data security (life cycle) • Originally developed for financial industry; uses CBEFF • APIs • Open: BioAPI, Java Card Biometric API; uses CBEFF • Proprietary: BAPI …what is Microsoft planning? • XCBF • XML Common Biometric Format from OASIS; uses CBEFF • Mechanisms for secure transmission, storage, integrity, & privacy of biometrics

22. Biometric Standards • Recently from NIST… • Biometric Data Specification for Personal Identity Verification (PIV) • January 24, 2005 (Draft) • New standards governing interoperable use of identity credentials to allow physical and logical access to federal government locations and systems • Technical and formatting requirements for biometric credentials • Restricts values and practices for fingerprints and facial images • Geared toward FBI background checks and formatting data for a PIV card • CBEFF and BioAPI compliant

23. CBEFF - Overview • Framework for sharing raw or template data • Supports encryption & digital signature for security • File = SBH (header) + BSMB (data) + SB (signature) • Patrons identify the data format • Approved interchange formats • Finger Minutiae, Finger Pattern, Finger Image, Face Recognition, Iris, Signature/Sign, Hand Geometry

24. CBEFF Patron Formats • Format A – The CBEFF Data Structure • Patron: CBEFF • Small embedded or legacy systems, limited storage • No data exchange between systems • Format B – The BioAPI Specification Biometric Identification Record (BIR) Format • Patron: BioAPI Consortium • BioAPI compliant systems • Client / server data exchange • Format C – ANSI X9.84 Biometric Object • Patron: ANSI Subcommittee X9, Working Group F4 • Large systems • Data exchange in a secure manner with authentication • Format D – Biometric Information Data Objects for Use Within Smart Cards or Other Tokens (recent)… e.g. Java Card

25. Wireless Advantages • Mobility • Flexibility • Easier to relocate and configure • More scalable • Cost • No cost due to physical barriers, private property. • Productivity • More opportunity to connect • Aesthetics • No clutter from wires • Robustness • Less physical infrastructure to damage and repair

26. Wireless Disadvantages • Lower channel capacity • Limited spectrum available • Power restrictions • Noise levels • Noise and interference • Frequency allocation • U.S. – FCC • Greater security concern • Information traveling in free space

27. Wireless Protocols • Network domains • Broadband • IEEE 802.16, Worldwide Interoperability for Microwave Access (WiMAX) – framework, not single system or class of service • Cellular networks • Global System for Mobile communication (GSM) • Universal Mobile Telecommunications System (UMTS =WCDMA) • Cordless systems • Time Division Multiple Access (TDMA) • Time Division Duplex (TDD) • Mobile Internet Protocol (Mobile IP) • Wireless Local Area Network (WLAN) • IEEE 802.11 (Wi-Fi) a,b,g (n … not yet ratified) • Wireless Personal Area Network (WPAN) • IrDA, Bluetooth, ultra wideband, wireless USB • Home Automation (narrow band) • Infineon, ZigBee, Z-Wave

28. Wireless Protocol Comparison Source: PC Magazine, March 22, 2004

29. Security and Protocols • Security domains • Application security • Wireless Application Protocol (WAP) • Uses Wireless Transport Layer Security (WTLS) • Current Class 2 devices based on IETF SSL/TLS • Future Class 3 devices will use a WAP Identity Module (WIM) • Web services • Simple Object Access Protocol (SOAP) – toolkits available for Java & .NET • Operating system security (Java run-time, Palm OS, Microsoft Windows CE) • Device security (PINs, pass-phrases, biometrics) • Security of wireless protocols • IEEE 802.11 (Wi-Fi) • Wireless Encryption Protocol (WEP)… weak and flawed • Wi-Fi Protected Access (WPA). Uses Temporal Key Integrity Protocol (TKIP) • IEEE 802.11i – Wireless Security spec. (WPA, AES, FIPS 140-2 compliant) • Authentication security • Remote Authentication Dial In User Service (RADIUS) • Kerberos • SSL

30. Network Encryption • Secure Shell (SSH) • Application Layer • Secure remote connection replacement for telnet, rlogin, rsh • Secure Socket Layer (SSL) • Transport Layer Security (TLS) • Uses TCP & has specific port numbers • Main use is HTTPS (port 443) • Internet Protocol Security (IPSec) • Network Layer • Includes a key management protocol • Included in IPv6

31. Network System Architecture • Where does authentication happen? • Device • Data not externally transmitted • Local Computer • Data transmitted between device(s) and PC (WPAN) • LAN-Connected Computer • Data transmitted locally (WLAN) • Remote Computer • Data transmitted remotely (WWAN) • Application dependent • Data transmitted between capture device and database • Database template storage requirement = template size * number of templates

32. Avenues of Attack = wireless LAN- connected Computer Local Computer LAN Remote Computer Capture Device WAN

33. Wireless Security Issues • Denial of Service (DoS) • Jamming…Use Spread Spectrum (DSSS, FHSS) technology • As a device battery attack, i.e., more processing = more battery usage • Eavesdropping • Signal is in the open air (war dialing) • Theft or loss of device • Due to size, portability, and utility • Dependency on public-shared infrastructure • What security is in place? • Masquerading • Rogue clients pretend to be legitimate endpoint • Rogue access points trick clients to logging in • Malware • Worms (Cabir) and Viruses (Timfonica, Phage) on wireless devices • Use Antivirus software

34. Wireless Security Paradox • We use wireless devices for convenience • Security measures often decrease convenience and performance • Result: Security features are often disabled or given lower priority

35. System Design Considerations • Verification • Are you who you claim to be (or are supposed to be)? • 1:1 matching • Usually consensual • Typically smaller template databases • Authorization (computer, network, building) • Identification • Who are you? • 1:n matching • Often no explicit consent or awareness • Typically larger template databases • Surveillance (homeland and border security), forensics, criminal investigation (AFIS) • Why not both? • i.e. You are not who you say you are, so who are you?

36. Scenario: Biometrics at the Airport • Workforce security • Biometric authentication • Identify all employees who require restricted area access • ID card encoded to protect data • Biometric scanning devices networked at access control points to permit/deny access • Facility integrity • Employees w/ vehicle access must be authenticated via biometrics • Access control within aircraft • Biometric devices for authorized personnel to access sensitive areas within aircraft • Communications infrastructure • Networked biometric scanning stations • Passenger security • Authenticate passengers with passports or ID cards containing encoded biometrics • Identify suspicious or unknown people with biometric surveillance

37. Putting it Together • How do we maximize advantages and minimize disadvantages when a biometric system is combined with a wireless system for an optimal wireless biometric system?

38. Future Research • Pattern for “fuzzy” matching? • Biometrics, digital watermarks, IDS, search engines • Biometric cryptography • Biometric key generation • Fuzzy matching methodologies • Embedding biometric keys within wireless protocols • X.509 certificates • Protocol payload area • Protocol header (authentication) area • Use coefficients? (polynomial, elliptic curve)