Transcript Slides

TOWARDS QUASI-REALTIME
THEFT-EVIDENT MECHANISM FOR
PORTABLE ARTIFACTS USING
NEAR-FIELD RFID
Kirti Chawla@ , Sunil K. Vuppala$, Puneet Gupta$
UNIVERSITY OF VIRGINIA, CHARLOTTESVILLE@
SET LABS, INFOSYS TECHNOLOGIES$
@ Weblink: http://www.cs.virginia.edu/~kc5dm
$ Weblink: http://www.infosys.com/technology/setlabs-briefings.asp
2 SIGNIFICANT DEVELOPMENTS
Quick Biased Inference
Estimated High Near
Term Projected Growth
Increased
Portable Device
Density Per
Capita
10 %
Source: Gartner Research (http://www.gartner.com)
Increased
reliance on
portable
devices
Susceptible to
misuse or theft
2
PROBLEM STATEMENT
To mitigate/minimize/deter the effect of theft with respect to portable devices using low-cost technology.
Challenges/Requirements
Opportunity/Target Devices
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Space Constraints
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Portable Audio Player
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Power Constraints
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Portable Video Player
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Mobility Constraints
•
Smartphone
•
Realtime Evidence of Theft
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Personal Digital Assistant
•
Cost/Effort
•
and many more …
Candidates
•
Wired Technology
× Cannot be applied in general due to
mobility constraints
•
15 %
Wireless Technology
•
Wi-Fi
 RFID (meets the requirements)
•
ZigBee
•
…
3
BRIEF INTRODUCTION TO RFID
Definition: RFID or Radio Frequency Identification is a technology for wireless recognition with the help of
radio waves.
A Tag or Transponder consists of a microchip that
Tag or
stores data and a coupling element, such as coiled
Transponder antenna, which is used to communicate via radio
frequency. 3 tag-type : Active, Passive & Hybrid
RFID System
Reader or
Transceiver
Data
Processing
System
Active RFID Tag
20 %
• Has a battery
• Long operating range
A Reader or Transceiver consists of radio frequency
module, a control unit and a coupling element to
interrogate electronic tags via RF communication
2 operating-fields : Near-Field & Far-Field
A Data Processing System takes data read by RFID
reader and stores it in a database. Various operations
on the data can be performed (manipulate, view etc.)
Applications: Object identification & tracking etc.
Passive RFID Tag
• No battery
• Short operating range
Suggestion: Viewers are advised to lookup terms for detailed definitions.
RFID Reader
4
• Operates in Near-Field or Far-Field
• Uses load modulation or backscatter
for communication with Tag
PROPOSED SOLUTION
DESIGN: BASICS
Requirements on underlying RFID carrier
•
•
Operation Field: Near-Field (Frequency ≤ 13.56 MHz), i.e. LF or HF
Operating Distance: Up to 1 meter(s)
Signal strength vis-à-vis distance relationship
S'=SxF(d)
where. the symbols have following meaning:
d = Distance
S = Signal strength at Point of origin of RF Signal
S' = Signal strength at point of reference of RF Signal
1
; Near-field RF Signal

 d6
F(d) = 
 1 ; Far-field RF Signal

 d2
25 %
How can this
underlying property of
Near-Field RFID signal
be used for solving
Problem Statement ??
Design Intuition 1: Shorter operating distance  low antenna power
Suggestion: Design decision intuition clears up as the presentation goes forward
5
PROPOSED SOLUTION
DESIGN: SYSTEM MODEL
Intelligent
Artifact Model
System Model
Un-intelligent
Artifact Model
30 %
Design Intuition 2: ICGTA  Shorter operating distance
Artifact: Fancy name for device/object
ICGTA: Increased Chance of Guessing the Thief Around
6
PROPOSED SOLUTION
DESIGN: PACKET FORMAT
Descriptions of Packet Field
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ACN: Artifact Class Number
AN: Artifact Number
ER: Error Resilience
WCN: Wearable-band Class Number
WN: Wearable-band Number
PAWN: Portable Artifact Wearable-band Number
R-PAWN: Reader-PAWN
T-PAWN: Tag-PAWN
RFID
Reader
R-PAWN
Tag
T-PAWN
T-PAWN
How frequently
T-PAWN should be
fetched from Tag
given that we have
power constraints
??
35 %
Design Intuition 3: Protocol is needed between RFID reader and Tag
Suggestion: PAWN is not same as pawn in CHESS game
7
PROPOSED SOLUTION
DESIGN: ERROR CORRECTION MECHANISM
To minimize the effect of intentional/un-intentional corruption on data-in-transit.
Claim
RFID reader provides error correction mechanisms, like CRC
Suggestion
Error correction mechanism presented
here, (uses Hamming Code) adds
multi-bit per byte error-correction with
relatively low computation cost on
reader side to augment CRC
40 %
Design Intuition 4: Resilience against intentional/un-intentional corruption required
8
PROPOSED SOLUTION
DESIGN: THEFT-EVIDENT ALGORITHM
T-PAWN Fetch Strategy
•
•
•
•
•
Partition time into 2 slots, viz. Sleep and Sweep Interval
Reader sleeps in Sleep Interval
Reader looks for Tag in Sweep Interval
Sleep Interval ≥ Sweep Interval to meet power constraints
Frequent Entry-Exit of Wearable-band in Reader field, to
be monitored using thresholds of time instead of distance.
45 %
Design Intuition 5: Realtime or Quasi-Realtime evidence of theft is pertinent
PA: Portable Artifact with RFID Reader
WB: Wearable-band with Tag
ROI: Region of Interest {bounded by S’}
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PROPOSED SOLUTION
DESIGN: OPERATIONS
Your Un-intelligent portable artifact
PA1
PAN
PA2
WB
50 %
Design Intuition 6: Class numbers facilitates grouping of artifacts, viz. <PAI, WBI>
In above example, pairs are: <PA1, WB>, <PA2, WB> … <PAN, WB>
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PROPOSED SOLUTION
IMPLEMENTATION: ERT
ERT - Experimental RFID Tool:
55 %
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Written in C++
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~2K source lines
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Lightweight/WIN32 programming model
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Simulates Quasi-Realtime theft scenario
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Supports 1-on-1 operation mode
•
Supports selective error-correction mechanism
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User-configurable parameters for Sleep, sweep interval and more
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Support for audible alerts on THEFT_CONDITION
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Support for custom action on THEFT_CONDITION
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Supports multiple error correction modes
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Extensible to Client/Server architecture using WINSOCK
Implementation Intuition 1: Construct a tool to embody design concepts
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PROPOSED SOLUTION
IMPLEMENTATION: TEST BED
Standard USB Cable
60 %
ST Microelectronics SR176B-A3T/PRY series RFID Tags
ST Microelectronics CRX14 RFID Reader
Implementation Intuition 2: First iteration, second iteration, ...
Sincere Gratitude: Towards Dr. Rajat Moona, Professor, CSE, IIT Kanpur for providing STM NFC Kit
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RESULTS: ERROR CORRECTION
Multi-bit per byte error-correction to augment CRC on RFID Reader
65 %
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RESULTS: SNAPSHOT OF ERT
Quasi-Realtime Theft Evidence
Initialization of ERT
70 %
14
MERITS/DEMERITS
Merits
1. Low cost prototype embodying design concepts
2. Experimental test-bed for problem statement
3. Version 1.0 contains significant features
4. Minimal effort portable to other platforms
5. Pragmatic solution
ERT
75 %
Demerits
1. Extensive field testing required
2. Tag data is not encrypted
3. Tag-cloning possible (But cost of attack increases)
15
Wisdom: Create, Err, Refine, Create again, …
INTERESTING MERIT
Immune against operation in Faraday Cage
Lack of proximity of wearable-band to portable artifact in these cages will still result in THEFT_CONDITION
80 %
Daily life examples of Faraday Cages(s)
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•
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Elevators
Conference rooms equipped with noise-cancellation technology
…
16
INTERESTING DEMERIT
Frequent theft alarms may be nuisance to people-at-large
85 %
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Quick solution: User can configure theft alarms (enable/disable) through a user-interface
APPLICATIONS
IAM
Applications
1. Portable Audio Player
2. Portable Video Player
3. Smartphone
4. Blackberry
and more …
ERT
UAM
90 %
Applications
1. Documents
2. Wallet
3. Bag
4. ID-Card
and more …
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IAM: Intelligent Artifact Model
UAM: Un-intelligent Artifact Model
SUBSEQUENT WORK
Further work includes:
95 %
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Enabling Sharing operation mode (Intelligent Artifact Model)
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Enabling Multi-tag operation mode (Un-intelligent Artifact Model)
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Enabling Uni-tag operation mode (Un-intelligent Artifact Model)
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Adding support for different types of RFID reader(s)/tag(s)
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Integration with a given portable artifact
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QUESTIONS & ANSWERS