RFID Systems and Security and Privacy Implications - PowerPoint PPT Presentation

1 / 49
About This Presentation
Title:

RFID Systems and Security and Privacy Implications

Description:

Each scanned once only at checkout. Use RFID to combine supply chain ... Automated Check-out. Picture your refrigerator telling you that you're out of milk! ... – PowerPoint PPT presentation

Number of Views:169
Avg rating:3.0/5.0
Slides: 50
Provided by: nam5100
Category:

less

Transcript and Presenter's Notes

Title: RFID Systems and Security and Privacy Implications


1
RFID Systems and Security and Privacy Implications
Auto-ID Center Massachusetts Institute of
Technology www.autoidcenter.org
  • Sanjay E. Sarma
  • Stephen A. Weis
  • Daniel W. Engels

2
Auto-ID Center
  • International industry-sponsored research center
  • MIT, Cambridge University, and University of
    Adelaide
  • Design, develop, and deploy large-scale field
    trials including RFID projects

3
Overview
  • Radio Frequency Identification (RFID)
  • EPC System
  • Security Benefits and Threats
  • Future

4
Uses of Automatic-ID Systems
  • Access control and security
  • Tracking of products in Supply Chain
  • Id of products at Point of Sale
  • Most widely used is the Bar Code System

5
Potential Application of RFID
  • Consider supply chain and EAN-UCC bar codes
  • 5 billion bar codes scanned daily
  • Each scanned once only at checkout
  • Use RFID to combine supply chain management
    applications

6
Benefits of Supply Chain Management
  • Automated real-time inventory monitoring
  • Automated Quality Control
  • Automated Check-out
  • Picture your refrigerator telling you that youre
    out of milk! ?

7
Why not yet implemented
  • Cost too high. Needs to be lt0.10
  • Lack of standards and protocols
  • Security concerns similar in smart cards and
    wireless
  • Privacy issues Big Brother

8
RFID System Components
  • RFID Tag
  • Transponder
  • Located on the object
  • RFID Reader
  • Transceiver
  • Can read and write data to Tag
  • Data Processing Subsystem

9
Transponder
  • Consist of microchip that stores data and antenna
  • Active transponders have on-tag battery
  • Passive transponders obtain all power from the
    interrogation signal of reader
  • Active and passive only communicate when
    interrogate by transceiver

10
Transceiver
  • Consist of a RF module, a control unit, and a
    coupling element to interrogate tags via RF
    communication
  • Also have secondary interface to communicate with
    backend systems
  • Reads tags located in hostile environment and are
    obscured from view

11
Data Processing Subsystem
  • Backend System
  • Connected via high-speed network
  • Computers for business logic
  • Database storage
  • Also as simple as a reader attached to a cash
    register

12
RFID
  • Basic components of RFID system combine in the
    same manner
  • All objects are physically tagged with
    transponders
  • Type of tag used varies from application to
    application
  • Passive tags are most promising

13
RFID
  • Transceivers are strategically placed for given
    application
  • Access Control has readers near entrance
  • Sporting events have readers at the start and
    finish lines

14
Transceiver-Transponder Coupling and Communication
  • Passive tags obtain power from energy in EM field
    generated by reader
  • Limited resource require it to both get energy
    and communicate within narrow frequency band
    regulatory agencies

15
Inductive Coupling
  • Uses magnetic field to induce current in coupling
    element
  • Current charges the on-tag capacitor that
    provides operating voltage
  • This works only in the near-field of signal up
    to c/(2pf) meters

16
Inductive Coupling
  • Operating voltage at distance d is proportional
    to flux density at d
  • Magnetic field decreases in power proportional to
    1/d3 in near field
  • Flux density is max when R dv2, where R is
    radius of readers antenna coil

17
Far Field energy harvesting
  • Uses readers far field signal to power tag
  • Far field begins where near field ends
  • Signal incident upon the tag induces voltage at
    input terminals of the tag, which is detected by
    RF front-end circuitry and is used to charge
    capacitor

18
Passive tag power
  • Reader uses same signal to communicate with and
    power tag
  • Any modulation of signal causes power reduction
  • Modulating information spreads the signal
    referred to as side band.
  • Side band and max power is regulated

19
Transponder Communication
  • RFID systems generally use the Industrial-Scientif
    ic-Medical bands
  • In near field, communication is achieved via load
    modulation
  • In far field, backscatter is used. Backscatter
    is achieved by modulating the radar-cross section
    of tag antenna

20
Limitations of Passive Tag communication
  • Very little power available to digital portion of
    the IC, limited functionality
  • Length of transactions is limited
  • Length of power on
  • Duration within communication range
  • US regulations for 915 MHz limit transaction time
    to 400 ms
  • Limit of state information

21
Data Coding and Modulation
  • Determines bandwidth, integrity, and tag power
    consumption
  • Limited by the power modulation / demodulation
    capabilities of the tag
  • Readers are generally low bandwidth, due to
    government regulations
  • Passive tags can use high bandwidth

22
Coding
  • Level Codes
  • Non-Return-to-Zero
  • Return-to-Zero
  • Transition Codes
  • Manchester
  • Miller

23
Coding Considerations
  • Code must maintain power to tag as much as
    possible
  • Code must not consume too much bandwidth
  • Code must permit the detection of collisions

24
Coding for Readers and Tags
  • Reader to Tag uses PPM or PWM (lower bandwidth)
  • Tag to Reader uses Manchester or NRZ (higher
    bandwidth)

25
Modulation
  • RF communications typically modulate high
    frequency carrier signal to transmit baseband
    code
  • Three classes of digital modulation are ASK, FSK,
    and PSK.
  • ASK most common in 13.56 MHz load modulation
  • PSK most common in 915 MHz backscatter modulation

26
Tag Anti-Collision
  • Limited power consumption
  • State information may be unreliable
  • Collisions may be difficult to detect due to
    varying signal strengths
  • Cannot be assumed to hear one another

27
Algorithm Classification
  • Probabilistic
  • Tags respond in randomly generate times
  • Slotted Aloha scheme
  • Deterministic
  • Reader sorts through tags based on tag-ID
  • Binary tree-walking scheme

28
Algorithm Performance Trade-offs
  • Speed at which tags can be read
  • Outgoing bandwidth of reader signal
  • Bandwidth of return signal
  • Amount of state that can be reliable stored on
    tag
  • Tolerance of the algorithm to noise

29
Algorithm Performance Trade-offs
  • Cost of tag
  • Cost of reader
  • Ability to tolerate tags with enter and leave
    during interrogation period
  • Desire to count tags exactly as opposed to
    sampling
  • Range at which tags can be read

30
Regulations Effect
  • US regulations on 13.56 MHz bandwidth offer
    significantly less bandwidth, so Aloha is more
    common
  • 915 MHz bandwidth allows higher bandwidth, so
    deterministic algorithms are generally used

31
13.56 MHz Advantages
  • Frequency band available worldwide as an ISM
    frequency
  • Up to 1 meter reading distance in proximity /
    vicinity read
  • Robust reader-to-tag communication
  • Excellent immunity to environmental noise and
    electrical interference

32
13.56 MHz Benefits
  • Well-defined transponder interrogation zones
  • Minimal shielding effects from adjacent objects
    and the human body
  • Damping effects of water relatively small, field
    penetrates dense materials

33
915 MHz Benefits
  • Long range (from a few to several meters,
    depending on regulatory jurisdiction)
  • High data rates
  • Fast anti-collision and tags per second read rate
    capabilities

34
The EPC System
  • System that enables all objects to be connected
    to the Internet by adding an RFID tag to the
    object
  • EPC
  • ONS
  • SAVANT
  • Transponders

35
The EPC
  • Electronic Product Code
  • ID scheme designed to enable unique id of all
    physical objects
  • Only data stored on tag, since information about
    object is stored on network
  • EPC acts like a pointer

36
The ONS
  • Object Name Service
  • Directory service that maps EPS to IP
  • Based entirely on DNS
  • At the IP address, data is stored in XML and can
    be accessed via HTTP and SOAP

37
The ONS
  • Reduces power and memory requirements on tag
  • Transfer data communication to backend network,
    saving wireless bandwidth
  • Makes system more robust
  • Reduces size of microchip on tag

38
Savant
  • System based on hierarchical control and data
    management
  • Provides automated control functionality
  • Manages large volumes of data
  • Acts as a gateway for the reader network to the
    next higher level

39
Savant
  • Transfers computationally intensive functionality
    from tag to powered system
  • Any single point of failure has only local effect
  • Enables entire system to be scalable since reader
    sub-systems are added seamlessly

40
RFID Transponder
  • Most numerous parts of system
  • Most cost-sensitive part
  • Protocols designed for 13.56 MHz and 915 MHz
    frequencies
  • Implement a password-protected Self Destruct
    command

41
RFID Security Benefits and Threats
  • Airline passenger and baggage tracking made
    practical and less intrusive
  • Authentication systems already in use (key-less
    car entry)
  • Non-contact and non-line-of-sight
  • Promiscuity of tags

42
Previous Work
  • Contact-less and constrained computational
    resource similar to smart cards
  • Analysis of smart card security concerns similar
    to RFID
  • RFID especially susceptible to fault induction
    and power analysis attacks

43
Security Goals
  • Tags cannot compromise privacy of holders
  • Information should not be leaked to unauthorized
    readers
  • Should not be possible to build long-term
    tracking associations
  • Holders should be able to detect and disable tags
    they carry

44
Security Goals
  • Publicly available tag output should be
    randomized
  • Private tag contents should be protected by
    access control and encryption
  • Spoofing tags or readers should be difficult

45
Low-cost RFID Issues
  • Inexpensive read-only tags are promiscuous and
    allow automated monitoring privacy concern
  • Neither tags nor readers are authenticated
    security concern
  • Full implementation of privacy and security is
    costly cost concern

46
Possible solutions
  • Erase unique serial numbers at point of sale
    tracking still possible by associating
    constellations of tags
  • Public key cryptography too expensive
  • Shared key if one tag is compromised, entire
    batch is effected

47
Approach to RFID Protection
  • Use one-way hash function on tag meta-ID
  • When reader knows meta-ID, tag is unlocked and
    readable
  • After reader is finished, tag is locked
  • Tag has self-destruct mechanism to use if under
    attack

48
Future Research
  • Development of low cost crypto primitives hash
    functions, random number generators, etc.
  • Low cost hardware implementation w/o
    computational loss
  • Adaptation of symmetric encryption and public key
    algorithms from active tags into passive tags

49
Future Research
  • Developing protocols that make tags resilient to
    power interruption and fault induction.
  • Power loss graceful recovery of tags
  • Research on smart cards and other embedded systems
Write a Comment
User Comments (0)
About PowerShow.com