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RFID Security and Privacy:A Research Survey

Ari JuelsRSA Laboratories

IEEEJournal on Selected Areas in Communication (J-SAC) in 2006

Taesung Kim2008.10.28

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Contents

• RFID Overview– Tags, Readers, and Applications– Tag Singulation

• Security & Privacy Threats• Proposed Solutions

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RFID Overview

3

Tags (transponders)Attached to objects, “call out” identifying dataon a special radio frequency

02.3DFEX4.78AF51

EasyToll card #816

Reader (transceiver)Reads data off the tagswithout direct contact

Radio signal (contactless)Range: from 3-5 inches to 3 yards

DatabaseMatches tag IDs tophysical objects

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Tag Types

• Passive:– All power comes from a reader’s signal– Tags are inactive unless a reader activates them– Cheaper and smaller, but shorter range

• Semi-passive– On-board battery, but cannot initiate communication– Can serve as sensors, collect information from environment: for exam-

ple, “smart dust” for military applications• Active:

– On-board battery power– Can record sensor readings or perform calculations in the absence of a

reader– Longer read range

LF HF UHF

Freq. Range 125 - 134KHz 13.56 MHz 866 - 915MHz

Read Range 10 cm 1M 2-7 M

Application Smart Cards, Ticketing, animal tagging,Access Control

Small item management, supply chain,Anti-theft, library, transportation

Transportation vehicle ID, Access/Security, large item management, supply chain

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Applications

• Supply-chain management– logistics, inventory control, retail check-out

• Payment systems– ExxonMobil SpeedPass– I-Pass/EZ-Pass toll systems– Credit Cards

• Access Control– Passports

• Library books• Animal Tracking

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Security Challenge

• Low cost RFID tags have very limited re-sources– Typically have only 500-5,000 gates– May have up to a few hundred bits of storage– Tags cannot perform complex computations

• Most tags simply emit a static identifier when prompted

• Tags do not have the resources to allow for public-key or symmetric-key encryption systems

• EPC tags: $0.05, 250 – 1000 gates• AES requires 20,000 – 30,000 gates

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Consumer Privacy Problem

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Threats

• Tracking– Unauthorized use of a tag’s ID in order to gain informa-

tion about the location of a person or object– In a retail environment, a user can be associated with an

item at purchase time• Cloning/Replay

– Tags that emit static identifiers are very vulnerable– A thief could replace/rewrite a tag on an expensive item

• Denial-of-service– Conflicting RF signals can prevent legitimate tag com-

munication• Physical attacks

– Probing a tag to determine private data

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RFID Security Research

Blocking approachPractical approach

Cryptographic protocolapproach

“kill”“sleep/wake”Faraday CageActive JammingRe-labelling

Clipped TagMinimalistProxy model

Blocker TagHash-LockRandomized Hash-Lock

OSK modelMW modelHM modelLK model

Human authenticationapproach

HB and HB+ protocolHB++(first attempt) and HB++ protocolHB++ protocol by S. PiramuthuHB#

- Watchdog Tag- RFID Guardian- RFID Enhancer

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“kill” 기법과 “ sleep/wake” 기법

• “kill” and “sleep/wake” approach– “kill”

• Stop tag’s operation• Throw up the convenience of RFID system

– “sleep/wake”• Stop tag’s operation• Reused through wake command

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Re-Labelling 기법

• Inoue and Yarsuura’s approach– Splitting product-type identifiers and unique identifiers

across two RFID tags• Karjoth & Moskowiz’s approach

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Minimalist 기법

……

가명 5

가명

4가

명 3

가명 2가명 1

가명

nrequest request

response 가명 8 response 가명 2

가명 2

ID = 가명 8

……

가명 5

가명

4가

명 3

가명 2가명 1

가명

nrequest request

response 가명 n response 가명 5

? ? ? ? ?

가명 5<Tag 에 대한 첫 번째 request>

<Tag 에 대한 두 번째 request>

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Blocker Tag 기법

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Hash-Lock 기법

• Hash-Lock approach– Step 1 : Lock

ReaderTag DatabaseID

Select randomkey K and operate

Hash Function metaID = HK(ID)metaID

State of the tagchanges to

Lock

Tag

metaID, KStores metaIDand key K setto identify tags

(metaID1, K1)(metaID2, K2)

…(metaIDn, Kn)

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Hash-Lock 기법

• Hash-Lock approach– Step 2 : Unlock

ReaderTag Databasequery

metaIDTag state : Lock(metaID)

Tag

metaID

(metaID1, K1)(metaID2, K2)

…(metaIDn, Kn)

Finds key, ID set

by metaID

Key, IDKey

IDTag state : Unlock(ID)

Give pure informationof this tag

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RFID Guardian

• Scan logging : 인접 리더의 쿼리에 대한 감시• Tag logging : 태그의 ownership 제공 및 새로운

태그의 출현 감지• Tag-reader mediation

– Selective jamming

• Context-awareness – 시간 / 장소에 따라 알맞은 context 로 갱신

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Thank you!