VANISHING DOCUMENTSIMPACT ON PRIVACY

George B. DobbsChief Architect & Director Shared Services, Knights of Columbus Supreme Council

KNIGHTS OF COLUMBUS• Fraternal Benefit Society

with 1.7M members • United States, Canada, Latin

America, Philippines & Poland• Membership driven• Insures its members and

their families • Whole life, Term life, Fixed

annuities and Long term care products

• Career Agency System ~1400 agents

• Fortune 997, ~1.5 B Revenue

EPHEMERAL DOCUMENTS Give access – but only for a

while Owner’s copies are still valid Correspondent not fully trusted Example: shopping a business

plan Intentional forgetting

All copies vanish after an interval

Correspondent trusted but lazy Example: frank conversation in

email, later to be regretted.

PROVIDE ACCESS ONLY FOR A WHILE

Encrypt but control key access Correspondent must get key each time

(central control) or

Key is stored locally for a while for offline use

Requires client side container/code that could be attacked.

Commercial products in the Digital Rights Management category

Subject to legal or technical attacks on key holder

INTENTIONAL FORGETTING Encrypt but key access removed

after a while No action needed by user No retroactive retrieval by adversary

Even from storage such as caches, mail routers or backup tapes

No one can access after the interval expires even the owner has no access to they

key Research project at U. Washington Subject to key capture during the

interval Correspondent may copy message

during interval

VANISH RESEARCH PROJECT University of Washington

(Aug 2009) Use cases focus on

trusted but lazy correspondents

Splits symmetric key into parts

Used an open distributed hash table

AVOIDING A CENTRALIZED STORE Distributed Hash Tables

Used for many P2P applications Academic studies since 2001 Unless refreshed, DHT, times out entries

PREPARING A VANISHING DATA OBJECT

Pick a random symmetric key, K Encrypt the user data locally,

yielding C Pick a seed, L, for pseudo random

number generation Use L to generate indices in the

hash table x1..xn Divide the key into pieces k1..kn

where m parts are needed to compute the key, K. (Shamir Secret Sharing)

put(xi,ki) for i=1 to n destroys the local copy of the key, Sends {C,L} to correspondent

World-Wide DHT

HOW VANISH WORKS

Vanish

Encapsulate (data, timeout)

Vanish Data ObjectVDO = {C, L}

Secret Sharing

(M of N)

k1k2

kN

...k3

k1k2k3

kN

Ann

C = EK(data)

L

K

k1

k3kN

k2

9

VDO = {C, L}Carla

HOW VANISH WORKS

10

Vanish

Encapsulate (data, timeout)

Ann

C = EK(data)

World-Wide DHT

Vanish

Decapsulate (VDO = {C, L})

data

Carla

Secret Sharin

g(M of

N)

...k1

k3

kN

data = DK(C)

kNk3

k1

L L

KSecret

Sharing

(M of N)

X

VDO = {C, L}

k2k2

Vanish Data ObjectVDO = {C, L}

THE FIREFOX PLUG IN Implemented as an extension to the GPG plug in

Entirely client side

Shows potential for becoming mainstream

ATTACK Defeating Vanish (Sep 2009)

Researchers showed feasible to Infiltrate the open DHT Record all keys

Originators responded with improvements Use hybrid of open and closed DHT Closed DHT restricts entry of nodes into system

END OF TECHNICAL PART Next section

scratches at possible issues from an Enterprise point of view

Please suggest your own thoughts.

ORGANIZATIONAL DILEMMAS Lets suppose the

vanish ability becomes mainstream

What kinds of scenarios can we dream up?

LITIGATION HOLDS Legal framework

Stop the clock on document destruction Clearly this prohibits organizations

from originating these documents If someone does create a VDO

Keys and plaintext gone, but Crypto text is evidence that the document

existed What controls can we envision to

prevent their use?

INBOUND COMMUNICATIONS VDO’s could come from ‘outside’

Are there business reasons to allow this?

What about going ‘out’ to visit a VDO?

Are there cases when a VDO should not be opened?

Are there cases when it must be opened?

BUSINESS USES Probably few legitimate uses for large

commercial enterprises. Customer Service Brand Management

Public Safety Attorneys under privilege

GOING OUTSIDE TO VIEW Go to a website to view a VDO Does that constitute corporate knowledge?

Company uses social networking site Stay in contact with customers for customer

service, say Since VDO is mainstream,

A user turns it on for ALL communications, thinking that safer

But for enterprise, it’s a business transaction So….

Does it need to be ‘imported’ for preservation? Capture the key and ciphertext or just the

plaintext?

LETTING VDOS IN Email with a vanishing data object Options:

1. Detect and prevent entry, like spam2. Allow in, but prevent acquisition of keys,

through network policy.3. Allow in, but decode passing through gateway4. Allow in with quarantine & special handling

Is there a duty to preserve it? For e-Discovery? Would the court consider the unpacked as

equivalent? To prove it is equivalent you’d need the key

FOR SAFETY, MUST OPEN

Suppose clear text subject line contains a threat: “Bomb active. Defuse

instructions enclosed” Mail is received but

enterprise policies prevent acquisition of key

This scenario indicates some sort of handling

BRAND BUZZ Corporations sometimes

watch what is being said about them in public venues If social network acts as an

amplifier/repeater, and the VDOs time out say in 8 hours

Watcher scan cycle time would need to be less than the timeout

If today a daily scan is adequate, it might need to be every few hours

OUTBOUND COMMUNICATIONS Lying to a customer

EE or Agent promises something Controllable on internal equipment/email

Employee sends stolen company info User A with enterprise IP goes to sneaky.com Under the cover of HTTPS writes a VDO with

internal information User B an investor, foreign power etc, reads info In order to stop

Blacklist sneaky.com Terminate SSL at border

Intercept & decode, possibly quarantine Prevent anything that appears further encrypted.

NOT, PERHAPS, JERICHO, BUT Millions of consumer computers

Harnessed to provide some privacy Is an example of how

The walled garden model of the enterprise May no longer be sufficient

REFERENCES Vanish Self-Destructing Digital Data

http://vanish.cs.washington.edu/ New Technology to Make Digital Data Self-Destruct

http://www.nytimes.com/2009/07/21/science/21crypto.html

Distributed Hash Tables http://en.wikipedia.org/wiki/Distributed_hash_table

Attack http://z.cs.utexas.edu/users/osa/unvanish/papers/vanish-broken.pdf

Vanishing E-mail and Electronically Stored Information: an E-Discovery Hazard http://www.rlgsc.com/blog/ruminations/vanishing-electronic-data-ediscovery.html