friend-foe identification system

ECE 415 Senior Design Project Fall 2010

Justin AyvazianEric PutneyBen JohnsonMichael Ruth

Advisor: Professor Sandip Kundu

Friend-Foe Identification System

2ECE 415 Senior Design Project Fall 2010

Outline

Project Overview• Motivation• Problem Statement• System Design

System Diagrams and Operation• User and Data Flow Diagrams• Hardware Block Diagrams• Communication Scheme

Message Security• Password entry and transformation• RC5

Project Progress• Graphical Interface and Vehicle Tracking• Prototype Implementation• Future Consideration


Motivation

•Deaths per day due to Vehicle Bombings in Iraq

•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’


Problem Statement

Identify ground vehicles• Hijackings and bombings

Transmissions• Eavesdropping

Security• Digital Terrorism• Data Encryption and Decryption


System Overview


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


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


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

Scaling for Prototype


Outline






User-Level Diagram


Data Flow Diagram


Interrogator Unit


Transponder Unit


Identification Process


Packet Structures

4 message types:• Base Module:

• Request Identification

• Acknowledge ID/Update Randomization Value

• Vehicle Module:• Transmit Identification

• Acknowledge Randomization Value Update


Outline






Password Transformation

Why do passwords need to be transformed?• Avoid physical keys, use shared password • Future messages with same vehicle will be unique

Implementation• 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


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


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


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


RC5—Security Strength

Several strategies for breaking block cipher:• Exhaustive search• Statistical tests • Linear Cryptanalysis• Differential Cryptanalysis

Best public attack a variant of differential cryptanalysis Still requires unreasonable amounts of plaintext/ciphertext pairs


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


RC5—Operation Speed

Real-time requirement for transmissions Speed Results for RC5 – 32/12/16

What if we increase the number of rounds?• Achieves ≈220μs Key Expansion with 2000 rounds

Hypothesis: Verilog implementation will be more efficient than C

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


Outline






Interrogator User Interface

Output on the base module will be a GUI using a Google Maps overlay

Present• 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


Interrogator User Interface


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


Future Deliverables

Working Model• 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


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


Questions?


Sources

[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.

[2] R. Rivest. The RC5 Encryption Algorithm. March 20, 1997. Available at http://people.csail.mit.edu/rivest/Rivest-

TheRC5EncryptionAlgorithm.

[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

friend-foe identification system

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