Kaliski Wireless Security Wwc 2003

8/3/2019 Kaliski Wireless Security Wwc 2003

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Wireless Security

When Things Really Get InterestingBurt Kaliski, RSA Laboratories

World Wireless Congress

May 28, 2003


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Introduction

Cryptography plays a central rolein the wireless world

Emerging wireless world willrequire new types of security

One cryptographers perspectiveon interesting things to come


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VPN

Todays Wired World

Po

rtal
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VPN

Po

rtal

Current Wireless World

The wireless world today and in the near future is

like the wired world

without as many wires.
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Interoperability Is the Driver

From a security perspective, wired and wirelessapplications & networks are mostly similar today

Voice

E-mail

Web access

Games

Protocols are relatively similar as well, due tointeroperability requirements

W* Effect Considered Harmful (Rohit Khare, 1999)


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Roaming Users & On-Line Identities

Users are increasingly mobile

20M WLAN adaptors projected to ship this year(Gartner)

1M WLAN access points (Yankee)

Identity management is a key enablerCollaboration solutions must integrate with identity

and access management so that security and

personalization context can follow users (Burton)

Liberty Alliance is one forum for this work andcurrently includes participation from many wirelessvendors


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Solving Traditional Security Challenges

Many vendors including RSASecurity are working on thetraditional security challenges

Security solutions are critically

important to wireless technologytoday

But as a cryptography researcher,wireless technology tomorrow isconceptually interesting and is thefocus of this talk


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Where No Wires Have Gone Before

Emergingwireless worldencompasses totally new applications& networks that are impractical withwires

Wireless security protocols will be newas well


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VPN

Po

rtal

Emerging Wireless World

Emerging wireless world is unlike the wired

world

where no wires have gone before.
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A Proliferation of Devices

Enabled by wireless technologies, almostanything will soon be connected

Cameras

Sensors

Product tags

Currency

This presents new challenges in networkingand location privacy


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Privacy Challenges

Anything connected can potentially betracked

Who should be able to track what?

Balancing business benefits and privacy

e.g., track the product in the store, but not onthe consumer

Cryptography offers new tradeoffs


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Networking Challenges

Anything can be connected,

but to what?

Devices will need to connect toeach other and the network

througheach other But how can devices trust each

other to connect reliably?

Again new options from

cryptography


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Two Recent Research Examples

Micropayments for multi-hop cellular networks

Privacy protection for RFID tags

Chip (IC)Antenna
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Micropayments for Multi-Hop CellularNetworks

Markus Jakobsson (RSA Labs), Jean-PierreHubaux and Levente Buttyn (Swiss FederalInst. of Tech.)

Presented at Financial Cryptography 03

www.markus-jakobsson.com


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Multi-Hop Cellular

Advantages of multi-hop cellular: Reduced energy consumption Reduced interference

Fewer base stations with increased coverage Ad hoc networking


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Encouraging Honesty

Honest mobile nodes will forward packets for oneanother

Cheaters will forward just for themselves

May be difficult to tell the difference

How can honesty be encouraged?


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Solution: Micropayments

Attach micropaymentsto packets

cryptographic lottery tickets related to packet and

route

Honest nodes paid for winning tickets

or fixed amount based on claimed volume, with ticketsas evidence

Cheaters detected statistically

too many tickets as originator, not enough as forwarder

Micropayment schemes have been proposed formore general applications; this one is speciallyadapted to multi-hop


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The Solution in a Nutshell

Attachpaymenttoken

Check if thetoken is awinning ticket

If so, file claim

Check token

If correct,deliver packet

Submitrewardclaims

Accountingandauditinginformation

Debit/credit accounts

Identifyirregularities
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Privacy Protection for RFID Tags

Ari Juels (RSA Labs), Ron Rivest (MIT)and Mike Szydlo (RSA Labs)

Preprint, May 2003

theory.lcs.mit.edu/~rivest

Chip (IC)

Antenna


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What is an RFID Tag?

You probably own a few RFID tags

Contactless physical-access cards

Automated toll payment

Inventory tags

An RFID tag simply calls out its (unique) name or

static data at a range of several meters

74AB8

5F8KJ3

Plastic#3


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An Impending Explosion of Tags

Gillette has just ordered 500,000,000 RFID tags

Roughly two for every inhabitant of U.S.

Smart shelf application

Auto-ID Center at MIT

Walmart, Gillette, etc.RFID tags as next generation barcodes

Inventory control

European Central Bank plans to implant RFID tags inbanknotes by 2005

Anti-counterfeitingTracking of illicit monetary flows


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Other Applications

Prada, Soho NYC Personalize / accessorize

Recycling

Payment schemes

E.g., Mondex

Smart appliances House pets


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500 Euros

in walletSerial numbers:597387,389473

Wigmodel #4456

(cheap polyester)

30 items

of lingerie

Das Capitaland

Communist-

party handbook

Replacement hipmedical part #459382

Without Privacy Protection


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The Top Two Messages

Deployed navely, embedding of RFID tags presentsa serious danger to privacy.

The danger need not be quite so severe: There arereasonably practical ways to protect privacy.


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New Approach: Blocker Tag [JRS 03]

Blocker simulatesall possible tags!!

1,2,3,,2023 pairs

of sneakers and

(reading fails)


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How It Works

Tree-walking protocol for identifying tagsrecursively asks questions about tag serialnumbers:

Is there a tag whose next bit is a 1?

Is there a tag whose next bit is a 0? Blocker tag always says yes to bothquestions

Makes it seem like allserial numbers are present

Thus reader cannot figure out which ones areactuallypresent

Number of possible serial numbers is huge, soreader stalls


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Consumer Privacy + CommercialSecurity

Blocker tag system should protect privacy butstill avoid blocking unpurchaseditems

Blocker tag can be selective:

Privacy zones:Only block certain ranges of

RFID-tag serial numbersPolite blocking:Inform readers about which

ranges are privacy zones so that readers dont

stall

Zone mobility:Allow shops to move items into

privacy zone upon purchase


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Conclusions for Further Thinking

The wireless industry is weaving a computingand communications fabric where none existed

What happens then?

MITs Project Oxygen gives one glimpse, many

similar activities in progress With trustworthy, private, safeaccess,

computing benefits everyone


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Burt KaliskiDirector and Chief Scientist

RSA [email protected]

+1 781 515 7073

Kaliski Wireless Security Wwc 2003

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