Biometric Authentication in a Wireless Environment

Biometric Authentication in a
Wireless Environment
Dr. Mohammad Iqbal
Thanks to : Alex Kotlarchyk, Florida Atlantic University

7/16/2013

1

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

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Why Wireless Biometrics?


Combination of two rapidly growing
technologies

1. Biometric systems for verification and
identification
• Homeland Security

2. Wireless systems for mobility

• Over 1 trillion wireless phone min. in US,
2004



Common advantage is convenience

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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

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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

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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?

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Keyspace


Number of possible codewords (CW)
– Token

• 12-digit: CW = 10^12 CWs

– Password

• Full 62 ASCII alphanumeric chars used randomly in an 8char 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
–
–

–
–

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Iris ≈ 10^6 CWs
Fingerprint ≈ 10^4 CWs
Voice ≈ 10^3 CWs
Face ≈ 10 → 100 CWs
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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

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7/16/2013

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Source: Technology Review, June 2004

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





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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

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Biometric Authentication System

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Source: Podio, NIST

Template Size

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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.

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Biometric Authentication Threats

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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

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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

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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

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

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Biometric Cryptography (example)
01010 10101

00000 11111

Enroll
Template
(Encrypt) (key)

Password
(hashed)

Within
Threshold?

E(h(Pwd)) “stored”

compare
10000 10111
Hamming
Distance = 2

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01010 01010

Template
“live”
(key)
11010 11101
Verify
(Decrypt)

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Biometrics Standards



Common Biometric Exchange File Format (CBEFF)
ANSI-NIST-ITL-2000




American Association for Motor Vehicle Administration (AAMVA) DL/ID
2000
FBI




Intel Common Data Security Architecture (CDSA)
ANSI X9.84 – Biometric data security (life cycle)



APIs



XCBF

–
–

Data exchange & quality
Criminal identification

–
–

Wavelet Scalar Quantization (WSQ) – fingerprint image (de)compression
Electronic Fingerprint Transmission Standard (EFTS)

–

Originally developed for financial industry; uses CBEFF

–
–

Open: BioAPI, Java Card Biometric API; uses CBEFF
Proprietary: BAPI
…what is Microsoft planning?

–
–

XML Common Biometric Format from OASIS; uses CBEFF
Mechanisms for secure transmission, storage, integrity, & privacy of biometrics

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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

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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

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CBEFF Patron Formats


Format A – The CBEFF Data Structure



Format B – The BioAPI Specification Biometric Identification
Record (BIR) Format

– Patron: CBEFF
– Small embedded or legacy systems, limited storage
– No data exchange between systems
– Patron: BioAPI Consortium
– BioAPI compliant systems
– Client / server data exchange



Format C – ANSI X9.84 Biometric Object



Format D – Biometric Information Data Objects for Use Within
Smart Cards or Other Tokens (recent)… e.g. Java Card

– Patron: ANSI Subcommittee X9, Working Group F4
– Large systems
– Data exchange in a secure manner with authentication

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Wireless Advantages



Mobility
Flexibility



Cost



Productivity



Aesthetics



Robustness

– Easier to relocate and configure
– More scalable

– No cost due to physical barriers, private property.
– More opportunity to connect
– No clutter from wires
– Less physical infrastructure to damage and repair

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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

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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

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Wireless Protocol Comparison

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Source: PC Magazine, March 22, 2004

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

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Network Encryption


Secure Shell (SSH)



Secure Socket Layer (SSL)



Internet Protocol Security (IPSec)

– Application Layer
– Secure remote connection replacement for telnet, rlogin,
rsh

– Transport Layer Security (TLS)
– Uses TCP & has specific port numbers
– Main use is HTTPS (port 443)
– Network Layer
– Includes a key management protocol
– Included in IPv6

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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

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Avenues of Attack

= wireless

LAN- connected Computer

Local Computer

LAN

Remote Computer
Capture
Device

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WAN

32

Wireless Security Issues


Denial of Service (DoS)



Eavesdropping



Theft or loss of device



Dependency on public-shared infrastructure



Masquerading



Malware

– Jamming…Use Spread Spectrum (DSSS, FHSS) technology
– As a device battery attack, i.e., more processing = more battery usage
– Signal is in the open air (war dialing)
– Due to size, portability, and utility

– What security is in place?

– Rogue clients pretend to be legitimate endpoint
– Rogue access points trick clients to logging in
– Worms (Cabir) and Viruses (Timfonica, Phage) on wireless devices
– Use Antivirus software

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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


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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)

–
–
–
–
–

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)

Identification

Why not both?

– i.e. You are not who you say you are, so who are you?

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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



Passenger security

– Networked biometric scanning stations
– Authenticate passengers with passports or ID cards containing
encoded biometrics
– Identify suspicious or unknown people with biometric surveillance

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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?

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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)

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