Friend-Foe Identification System
Justin Ayvazian
Eric Putney
Ben Johnson
Michael Ruth
Advisor: Professor Sandip Kundu
ECE 415 Senior Design Project Fall 2010
Outline
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Project Overview
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System Diagrams and Operation
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User and Data Flow Diagrams
Hardware Block Diagrams
Communication Scheme
Message Security
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Motivation
Problem Statement
System Design
Password entry and transformation
RC5
Project Progress
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Graphical Interface and Vehicle Tracking
Prototype Implementation
Future Consideration
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Motivation
•7,000 heavily armored Mine Resistant Ambush Protected (MRAP)
vehicles transported into Iraq from 07’ to 08’
•Accounts for drop in deaths since 2007
•Vehicle hijackings and digital attacks more frequent as a result
•Prominent in Afghanistan and Pakistan
•18 attacks on Pakistani soil, up to 13 vehicles hijacked per attack
(From August to November of 07’)
• Extrapolated, that’s over 2100 vehicles hijacked since August 07’
•Deaths per day due to Vehicle
Bombings in Iraq
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Problem Statement
 Identify ground vehicles
• Hijackings and bombings
 Transmissions
• Eavesdropping
 Security
• Digital Terrorism
• Data Encryption and Decryption
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System Overview
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Requirements Specification
 Vehicle mounted system
• Power efficient, compact, and stand-alone
 Identification and threat assessment of approaching vehicles
• 2 mile range on base for adequate reaction time
 Security
• Secure transmissions
• Prevent digital terrorism and impersonation of friendly
vehicles
• Password interface
• Prevent unknown hijackings of military vehicles
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Final Design Concept
 Prototype system with limited range
• Design hardware and communication modules, leave physical
method of transmission up to end user
 WiFi as wireless transmission method for prototype
• Well defined standards, inexpensive implementation
 Nios II FPGA Core
• Run C control code on top of hardware modules
• Ex: RC5 and WiFi Transmission
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Scaling for Prototype
 Time to react: 110 seconds for 2 mile range at 105 km/h
 Range: 2 miles -> 100 m
 Speed: 105 km/h -> 6.56 km/h
• GUI Applet: Vehicle’s speed is 1.83 m/s
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Outline

Project Overview
•
•
•

System Diagrams and Operation
•
•
•

User and Data Flow Diagrams
Hardware Block Diagrams
Communication Scheme
Message Security
•
•

Motivation
Problem Statement
System Design
Password entry and transformation
RC5
Project Progress
•
•
•
Graphical Interface and Vehicle Tracking
Prototype Implementation
Future Consideration
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User-Level Diagram
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Data Flow Diagram
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Interrogator Unit
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Transponder Unit
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Identification Process
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Packet Structures
 4 message types:
• Base Module:
• Request Identification
• Acknowledge ID/Update
Randomization Value
• Vehicle Module:
• Transmit Identification
• Acknowledge
Randomization Value
Update
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Outline

Project Overview
•
•
•

System Diagrams and Operation
•
•
•

User and Data Flow Diagrams
Hardware Block Diagrams
Communication Scheme
Message Security
•
•

Motivation
Problem Statement
System Design
Password entry and transformation
RC5
Project Progress
•
•
•
Graphical Interface and Vehicle Tracking
Prototype Implementation
Future Consideration
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Password Transformation
 Why do passwords need to be transformed?
• Avoid physical keys, use shared password
• Future messages with same vehicle will be unique
 Implementation
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Shared 16 bit password for all vehicles
Multiply by randomly generated 16-bit number
232 possible values
“Three strikes rule” - ~ 5x10-3 % chance of correctly
guessing password even if all other parts of the system
have been compromised
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Randomization Value Updating
 Updated through rolling encryption scheme
• Similar to system used for remote entry devices for cars
 Last message from base to vehicle sends new
randomization value
• Generated by base, stored by both vehicle and base
 Base stores current value and previous value of
randomization values
• Final message is vehicle to base
• Base must store both in case final transmission not
received by base but is sent by vehicle
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Message Encryption
 Encryption Requirements
• Real-time ciphering
• Robust algorithm to prevent cryptanalysis
 RC5
• Parameter-Based Symmetric Block Cipher
• Adaptable for speed and encryption strength
• Lightweight encryption algorithm  FAST
• Performs word-oriented operations  FAST
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RC5 Encryption Module
 Initial C-based implementation—Completed
• Timing trials from 32-bit XP OS, running on a 1.83 GHz
processor.
 Future Verilog implementation
• Timing Expectations
 Algorithm requirements:
• Strong Security
• Data Dependant rotations
• Fast Encryption, Decryption, and Key Expansion
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RC5—Security Strength
 Several strategies for breaking block cipher:
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Exhaustive search
Statistical tests
Linear Cryptanalysis
Differential Cryptanalysis
 Best public attack a variant of differential cryptanalysis
 Still requires
unreasonable
amounts of
plaintext/ciphertext
pairs
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RC5—Security Strength (cont.)
 Data Dependent Rotations
• Helps protect against differential cryptanalysis
• Coupled with the use of the password transformation,
identical messages will have different ciphertexts
• Prevents Timing analysis
 Strength against other known cryptanalysis methods
• Linear
• Exhaustive
• 2Bits_in_key attempts
• Statistical
• Data-dependent rotations/password randomization
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RC5—Operation Speed
 Real-time requirement for transmissions
 Speed Results for RC5 – 32/12/16
Processor Speed
Compiler
Key Expansion
Encryption/Decryption
bytes/second
90 MHz
16-bit Borland
220μs
22μs
36,000Bps
1.83GHz
32-bit GCC
>1μs
>1μs
>64MBps
 What if we increase the number of rounds?
• Achieves ≈220μs Key Expansion with 2000 rounds
 Hypothesis: Verilog implementation will be more
efficient than C
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Outline

Project Overview
•
•
•

System Diagrams and Operation
•
•
•

User and Data Flow Diagrams
Hardware Block Diagrams
Communication Scheme
Message Security
•
•

Motivation
Problem Statement
System Design
Password entry and transformation
RC5
Project Progress
•
•
•
Graphical Interface and Vehicle Tracking
Prototype Implementation
Future Consideration
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Interrogator User Interface
 Output on the base module will be a GUI using a
Google Maps overlay
 Present
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Used the longitude and latitude for UMass in demo
100 meters at UMass longitude is .001270
100 meters at UMass latitude is .0010
Range of base station is 100 meters
 Future
• Will be putting the GUI in an applet – need to acquire
license from Google
• Simulated path based on normal UMass walkways will be
used for demos– need GPS module before data can be
taken
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Interrogator User Interface
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Prototype Progress
 Transponder Unit (Vehicle):
• RC5
• Message encryption and decryption
• Key table generation
• Control Module
• Data parsing & concatenation
 Interrogator Unit (Base Station):
• RC5
• Message encryption and decryption
• Key table generation
• Control Module
• Data parsing & concatenation
• GUI implementation
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Future Deliverables
Working Model
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C and Verilog code
GUI
Implemented RC5 encryption scheme
Full Communication Between:
• GPS and Vehicle via USB
• Vehicle and Base Station via 802.11 protocols
• Base Station and GUI via USB
Equipment
• GPS via USB port
• WiFi Transceivers via USB ports
• Altera DE2 Boards
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Future Considerations
 Ad Hoc networking
• Allow vehicles to identify one another away from base
 Enhanced driver identification system
• Increased protection against hijackings
• Example: fingerprint scan
• More specific to military personnel
 Anti-jamming
• Switch between 802.11 b and 802.11 g to prevent narrow
band jamming
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Questions?
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Sources
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[1] B. Kaliski, Y. Yin. On the Security of the RC5 Encryption
Algorithm. v1.0, September 1998. Available at
ftp://ftp.rsasecurity.com/pub/rsalabs/rc5/rc5-report.pdf.
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[2] R. Rivest. The RC5 Encryption Algorithm. March 20, 1997.
Available at http://people.csail.mit.edu/rivest/RivestTheRC5EncryptionAlgorithm.
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[3] R. Rivest. The RC5 Algorithm. Dr. Dobbs Journal number
226, pages 146-148. January 1995. Available at
http://people.csail.mit.edu/rivest/Rivest-rc5rev.pdf
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