Online Online Privacy Privacy

TechnologiesTechnologiesDr. Lorrie Faith Cranor

AT&T Labs-Research

http://www.research.att.com/~lorrie/

NTIA Online Privacy Technologies WorkshopNTIA Online Privacy Technologies Workshop

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Why is Cathy concerned?Why is Cathy concerned?

Cathy March 1, 2000

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How did Irving find this out? How did Irving find this out?

He snooped her email

He looked at the files on her computer

He observed the “chatter” sent by her browser

He set cookies through banner ads and “web bugs” that allowed him to track her activities across web sites

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What do browsers chatter What do browsers chatter about?about?

Browsers chatter aboutIP address, domain

name, organization, Referring pagePlatform: O/S, browser What information is

requestedURLs and search terms

Cookies

To anyone who might be listeningEnd serversSystem administratorsInternet Service

ProvidersOther third parties

Advertising networks

Anyone who might subpoena log files later

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A typical HTTP requestA typical HTTP requestGET /retail/searchresults.asp?qu=beer HTTP/1.0Referer: http://www.us.buy.com/default.aspUser-Agent: Mozilla/4.75 [en] (X11; U; NetBSD 1.5_ALPHA

i386)Host: www.us.buy.comAccept: image/gif, image/jpeg, image/pjpeg, */*Accept-Language: enCookie: buycountry=us; dcLocName=Basket;

dcCatID=6773; dcLocID=6773; dcAd=buybasket; loc=; parentLocName=Basket; parentLoc=6773; ShopperManager%2F=ShopperManager%2F=66FUQULL0QBT8MMTVSC5MMNKBJFWDVH7; Store=107; Category=0

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What about cookies?What about cookies? Cookies can be useful

used like a staple to attach multiple parts of a form together

used to identify you when you return to a web site so you don’t have to remember a password

used to help web sites understand how people use them

Cookies can be harmfulused to profile users and track their activities without

their knowledge, especially across web sites

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YOU

Searchengine

Ad

Search formedical

information

BookStore

Ad

Buy book

With cooperationfrom book store, ad

company can get your name and address from

book order andlink them to your search

Readcookie

Setcookie

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Web bugsWeb bugs Invisible “images” embedded in web pages

that cause cookies to be transferred

Work just like banner ads from ad networks, but you can’t see them unless you look at the code behind a web page

Also embedded in HTML formatted email messages

Can also use JavaScript to perform same function without cookies

For more info on web bugs see: http://www.privacyfoundation.org/education/

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Referer log problemsReferer log problems

GET methods result in values in URL

These URLs are sent in the REFERER header to next host

Example: http://www.merchant.com/cgi_bin/order?name=Tom+Jones&address=here+there&credit+card=234876923234&PIN=1234& -> index.html

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Low tech solutionsLow tech solutions Wander around cyber cafes

Use free e-mail service instead of ISP

Set up a pre-paid cash account with ISPgive all phony information

Obtain unusual domain name and get people you trust as name servers

Forge e-mail, spoof IP, etc.

. . . And don’t give out any personally-identifiable data!

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Types of software toolsTypes of software tools Anonymity and

pseudonymity tools Anonymizing proxies Mix Networks and similar

web anonymity toolsOnion routingCrowdsFreedom

Anonymous email

Encryption tools File encryption Email encryption Encrypted network

connections

Filters Cookie cutters Child protection software

Information and transparency tools Identity management tools P3P

Other tools Privacy-friendly search

engines Computer “cleaners” Tools to facilitate access

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Regulatoryand

self-regulatoryframework

Regulatoryand

self-regulatoryframework

ServiceUser

The Internet

Secure channel

P3P user agent

Cookie cutter

Anonymizing agent

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Anonymizing proxyAnonymizing proxy Acts as a proxy for users

Hides information from end servers

Sees all web traffic

Free and subscription services available

Some free services add advertisements to web pages

ProxyBrowserEnd

Server

Request Request

ReplyReply

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http://www.anonymizer.com

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Pseudonymity toolsPseudonymity tools

quote.com

nytimes.com

expedia.com

mfjh

asef

dsfdf

Proxy

Automatically generate user names, passwords,email addresses, etc. unique to each web site you visit

username

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CUSTOMER PC

Public Identity Private IdentityJohn Doe iPrivacy ABCDEF1 MAIN ST 1 dQg85xP26Kansas City, KS Kansas City, KS11122 11122Doe@ isp .com ABCDEF@iPrivacy.com

iPrivacy private shipping iPrivacy private shipping labelslabels

WEB FORM

Name : iPrivacy ABCDEF

Address:: 1 dQg85xP26

City : Kansas CityState : KSZip : 11122Email : ABCDEF @iPrivacy.com

WEB e- Tailer

Order Entry System Submit Credit Card

If Authorized Ship Product

Shipping SubsystemInput Private Identity

Decode AddressPRINT LABEL

iPrivacy ABCDEF

1 MAIN STKansas City, KS 11122

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Incogno SafeZoneIncogno SafeZoneThe merchant offers Incogno SafeZone from its site

Upon checkout, the buyer enters personal information into The Incogno SafeZone – a separate server.

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Incogno SafeZoneIncogno SafeZoneIncogno reinforces that the purchase is anonymous.

The anonymous purchase is complete with no added software installation or setup for the buyer.

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PrivadaPrivada

Multi-server design to shield real-world info

Info is compartmentalized & encrypted, then processed by servers on a need-to-know basis

Online identities and activity are kept distinct from real-world identities

Patent-pending privacy management infrastructure

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B, kAC kB

Mixes [Chaum81]Mixes [Chaum81]

Sender routes message randomly through network of “Mixes”, using layered public-key encryption.

Mix A

dest,msg kC

C kBdest,msg kC

dest,msg kC

Sender Destination

msgMix C

kX = encrypted with public key of Mix X

Mix B

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Freedom by Zero-Freedom by Zero-KnowledgeKnowledge

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Freedom nymsFreedom nyms

Create multiple psuedonyms

Surf without a nym

Select a nym and surf

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CrowdsCrowds Experimental system developed at AT&T Research

Users join a Crowd of other users

Web requests from the crowd cannot be linked to any individual

Protection fromend serversother crowd memberssystem administratorseavesdroppers

First system to hide data shadow on the web without trusting a central authority

http://www.research.att.com/projects/crowds/

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Crowds illustratedCrowds illustrated

1

2

6

3

5

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3

5

1

6

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Crowd members Web servers

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Anonymous emailAnonymous email

Anonymous remailers allow people to send email anonymously

Similar to anonymous web proxies

Some can be chained and work like mixes

http://anon.efga.org/~rlist

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Encryption toolsEncryption tools File encryption

Email encryptionMany email programs include encryption features built

in or available as plug-insWeb-based encrypted email

Email that self-destructs – Disappearing, Inc.

Encrypted network connectionsSecure socket layer (SSL)Secure shell (SSH)Virtual private networks

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Disappearing, Inc.Disappearing, Inc.

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FiltersFilters Cookie Cutters

Block cookies, allow for more fine-grained cookie control, etc.

Some also filter ads, referer header, and browser chatter

http://www.junkbusters.com/ht/en/links.html#measures

Child Protection SoftwareBlock the transmission of certain information via email,

chat rooms, or web forms when child is using computer

Limit who a child can email or chat withhttp://www.getnetwise.org/

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Identity management toolsIdentity management tools Services and tools that

help people manage their online identities Offer convenience of not

having to retype data and/or remember passwords

Some let consumers opt-in to targeted advertising (permission marketing), sharing data with sites, etc.

Some pay consumers for providing data

Some check for privacy policies before releasing data or require minimum privacy standards for participating sites

Examples AllAdvantage.com DigitalMe Enonymous Lumeria Persona PrivacyBank.com

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Consumer fills out Persona with personal information

Consumer can decide how each field is shared with online businesses and 3rd parties

PersonaPersona

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Allows user to accept or reject

cookies while surfing

Cookie Watcher tells users when cookies are being dropped

P3P Viewer alerts user to

site with valid P3P

policy; allows comparison

to user’s privacy settings

Pop-up Menu

PersonaValetPersonaValet A free toolbar

Four views provide features that include Cookie Management, P3P reader, automatic log-in, form-fill, quick access to top sites,

search engines & comparison capabilities

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PrivacyBank.ComPrivacyBank.Com PrivacyBankbookmark

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Infomediary example: PrivacyBank

PrivacyBankbookmark

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Platform for Privacy Preferences Platform for Privacy Preferences (P3P)(P3P)

Offers an easy way for web sites to communicate about their privacy policies in a standard machine-readable formatCan be deployed using existing web servers

This will enable the development of tools (built into browsers or separate applications) that:Provide snapshots of sites’ policiesCompare policies with user preferencesAlert and advise the user

For more info see http://www.w3.org/P3P/

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Using P3P on your Web siteUsing P3P on your Web site1. Formulate privacy policy

2. Translate privacy policy into P3P format Use a policy generator tool

3. Place P3P policy on web site One policy for entire site or multiple policies for different parts of

the site

4. Associate policy with web resources: Place P3P policy reference file (which identifies location of

relevant policy file) at well-known location on server; Configure server to insert P3P header with link to P3P policy

reference file; or Insert link to P3P policy reference file in HTML content

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The P3P vocabularyThe P3P vocabulary Who is collecting data?

What data is collected?

For what purpose will data be used?

Is there an ability to opt-in or opt-out of some data uses?

Who are the data recipients (anyone beyond the data collector)?

To what information does the data collector provide access?

What is the data retention policy?

How will disputes about the policy be resolved?

Where is the human-readable privacy policy?

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TransparencyTransparency P3P clients can

check a privacy policy each time it changes

P3P clients can check privacy policies on all objects in a web page, including ads and invisible images

http://adforce.imgis.com/?adlink|2|68523|1|146|ADFORCE

http://www.att.com/accessatt/

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Microsoft/AT&T P3P browser helper Microsoft/AT&T P3P browser helper objectobject

A prototype tool designed to work with Microsoft Internet Explorer Browser

Not yet fully tested, still missing some features

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Preference settings

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When preferences are changed toDisallow profiling, the privacy checkwarns us that this site profiles visitors

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IDcide Privacy CompanionIDcide Privacy Companion A browser plug-in that adds functionality to Netscape

or Internet Explorer browsers

Includes icons to let users know that sites use first- and/or third-party cookies

Enables users to select a privacy level that controls the cookie types allowed (1st or 3rd party)

Prevents data spills to 3rd parties through “referer”

Lets users view tracking history

Prototype P3P-enabled Privacy Companion allows for more fine-grained automatic decision making based on P3P policies

http://www.idcide.com

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Searching for a P3P policy

No P3P policy found

P3P policy isNOT acceptable

P3P policy isacceptable

IDcide P3P Icons

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Double clicking on the P3P icon indicates wherethe site’s policy differs from the user’s preferences

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YOUpowered Orby Privacy YOUpowered Orby Privacy PlusPlus

A tool bar that sits at the top of a user’s desktop and allows a user toAccept or deny cookies while surfing Decide how, when and where to share

personal information Store website passwords Enjoy the convenience of "one-click" form-fill

P3P features in prototype automatically rate web sites based on their P3P policies

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TrustMeter

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Orby cookie prompt

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Orby preference setting menu

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IBM P3P Policy EditorIBM P3P Policy Editor

Allows web sites to create privacy policies in P3P and human-readable format

Drag and drop interface

Available from IBM AlphaWorks site: http://www.alphaworks.ibm.com/tech/p3peditor

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Sites can list the typesof data theycollect

And view the correspondingP3P policy

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Templates allow sites to start witha pre-defined policyand customize it tomeet their needs

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PrivacyBot.comPrivacyBot.com

Allows webmasters to fill out an online questionnaire to automatically create a human-readable privacy policy and a P3P policy

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YOUpowered Consumer Trust Policy Manager WizardYOUpowered Consumer Trust Policy Manager Wizard

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Other toolsOther tools

Privacy-friendly search enginesTopClick

Computer “cleaners”Window Washer – removes all traces of what

web sites you visited, what files you viewed, and what files you deleted

Tools to facilitate accessPrivacyRight

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Tools work togetherTools work together P3P tools

help users understand privacy policies

Seal programs and regulations help ensure that sites comply with their policies

Anonymity tools and filtering toolsreduce the amount of information revealed while

browsing

Encryption tools secure data in transit and storage

Laws and codes of practice provide a base line level for acceptable policies

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Download these slidesDownload these slides

http://www.research.att.com/~lorrie/privacy/NTIA-0900.ppt