V ANISHING D OCUMENTS I MPACT ON P RIVACY George B. Dobbs Chief Architect & Director Shared Services, Knights of Columbus Supreme Council

K NIGHTS OF C OLUMBUS 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

E PHEMERAL D OCUMENTS 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 , later to be regretted.

P ROVIDE 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

I NTENTIONAL F ORGETTING 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

V ANISH R ESEARCH P ROJECT University of Washington (Aug 2009) Use cases focus on trusted but lazy correspondents Splits symmetric key into parts Used an open distributed hash table

A VOIDING A CENTRALIZED STORE Distributed Hash Tables Used for many P2P applications Academic studies since 2001 Unless refreshed, DHT, times out entries

P REPARING A V ANISHING D ATA O BJECT 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 x 1..x n Divide the key into pieces k 1..k n where m parts are needed to compute the key, K. (Shamir Secret Sharing) put(x i,k i ) for i=1 to n destroys the local copy of the key, Sends {C,L} to correspondent

World-Wide DHT H OW V ANISH W ORKS Vanish Encapsulate (data, timeout) Vanish Data Object VDO = {C, L} Secret Sharing (M of N) k1k1 k2k2 kNkN... k3k3 Random indexes k1k1 k2k2 k3k3 kNkN Ann C = E K (data) L K k1k1 k3k3 kNkN k2k2 9 VDO = {C, L} Carla

H OW V ANISH W ORKS 10 Vanish Encapsulate (data, timeout) Random indexes Ann C = E K (data) World-Wide DHT Vanish Decapsulate (VDO = {C, L}) data Carla Secret Sharing (M of N)... Random indexes k1k1 k3k3 kNkN data = D K (C) kNkN k3k3 k1k1 LL K Secret Sharing (M of N) X VDO = {C, L} k2k2 k2k2 Vanish Data Object VDO = {C, L}

T HE F IREFOX P LUG IN  Implemented as an extension to the GPG plug in  Entirely client side  Shows potential for becoming mainstream

A TTACK 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

E ND OF T ECHNICAL P ART Next section scratches at possible issues from an Enterprise point of view Please suggest your own thoughts.

O RGANIZATIONAL D ILEMMAS Lets suppose the vanish ability becomes mainstream What kinds of scenarios can we dream up?

L ITIGATION H OLDS 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?

I NBOUND C OMMUNICATIONS 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?

B USINESS U SES Probably few legitimate uses for large commercial enterprises. Customer Service Brand Management Public Safety Attorneys under privilege

G OING 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?

L ETTING VDO S IN with a vanishing data object Options: 1. Detect and prevent entry, like spam 2. Allow in, but prevent acquisition of keys, through network policy. 3. Allow in, but decode passing through gateway 4. 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

F OR S AFETY, M UST 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

B RAND B UZZ 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

O UTBOUND C OMMUNICATIONS Lying to a customer EE or Agent promises something Controllable on internal equipment/ 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.

N OT, P ERHAPS, J ERICHO, B UT 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

R EFERENCES Vanish Self-Destructing Digital Data New Technology to Make Digital Data Self-Destruct Distributed Hash Tables Attack broken.pdf broken.pdf Vanishing and Electronically Stored Information: an E-Discovery Hazard electronic-data-ediscovery.html electronic-data-ediscovery.html