L12: Privacy Protecting Technologies

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L12 Privacy Protecting Technologies

• CSCI E-170December 7, 2004Simson L. Garfinkel

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Agenda

• HW6 Grades sent out. (sorry for the delay)
• Projects How are people doing?
• Privacy Protecting Technologies
• Course Evaluations
• In class or on the website

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Technology Value Neutral?

• Does technology, on average, help or hinder
  personal privacy?

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The Big Idea

• We can use technology to improve privacy

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Privacy Protecting Tools for Web Browsing

• Browser
• pop-up blocking
• Client Side
• Web proxy works with anything
• IE plug-in helper object
• Web Service
• Browser agnostic
• You must trust the service!

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Browser protection

• Safari and Mozilla provide
• pop-up blocking
• Cookie Management
• Demo look at whats offered

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Client-side Protection

• Ad-Subtract
• http//www.intermute.com/adsubtract/
• Bugnosis
• http//www.bugnosis.org/
• SpoofGuard
• http//crypto.stanford.edu/SpoofGuard/
• WebPwdHash
• http//crypto.stanford.edu/PwdHash/

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Ad Subtract
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Search Sanity
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Ad Subtract Client-Side Java Proxy

• Advantages
• Multiplatform
• Easy to debug
• Client/server

• Disadvantages
• Doesnt work with SSL
• Install footprint
• Need to parse HTML

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Ad Blockers

• Ad-Subtract
• Junkbuster Proxy
• Discussion?

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Bugnosis
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Bugnosis

• Features
• Browser helper object
• Accesses HTTP HTTPS
• Downloads updates
• Designed for journalists

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SpoofGuard

• Browser plug-in (IE only)
• Rule-based spamassassin for websites

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SpoofGuard Controls

• Not quite sure how to set these? Youre not alone

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SpoofGuard rules

• Domain Name Check
• http//www.paypai.com/
• URL check
• http//www.paypai.com_at_123.123.123.123/
• Email Check
• Arriving at a URL by email is bad
• Password Field Check
• Lower threshold for pages asking for passwords
• Link Check
• Suspicious links are links that have suspicious
  URLs
• Image Check
• Images on one website similar to those on another
  website
• Password Tracking
• Password at one website same as another website

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SpoofGuard URL Check
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SpoofGuard Image Check
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SpoofGuard Download

• OpenSource - Good template for doing a browser
  plug-in
• Internet Explorer only
• http//crypto.stanford.edu/SpoofGuard/download.htm
  l
• Discussion?

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WebPwdHash

• The problem Users tend to use the same username
  password at every site
• The solution Hash the password with the domain
  at the browser and send the hash to the remote
  website

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WebPwdHash

• Advantages
• Each site gets a different password
• Protects against phishing
• Disadvantages
• Must trust the browser (doing that anyway)
• Cant run without the plug-in (unless you go to a
  remote website)
• Users must reset all of their passwords
• Doesnt work with handhelds, cell phones, etc.
• Discussion?

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Privacy Protecting Web Services

• Web Caches Open Proxies
• Remailers
• Anonymizer
• Anonymous Transport Services
• Freedom
• Onion Routing
• Anonymous Publishing Services

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Why use a privacy service?

• Prevent tracing to your IP address
• Get around a national, ISP, or business block
• China
• Saudi Arabia
• Fidelity

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Mix-Nets

• Anonymity Loves Company
• Chaums mix-net scheme
• 1 mix you trust the mixer
• More mixes -gt Less Trust
• Mixing needs to be in space and time

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Practical applications of mixers

• Anonymous Remailers
• Anonymous Browsing
• Anonymous Publishing

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Anonymous Remailers

• Anonymous posting on Usenet
• anon.penet.fi
• Based in Finland
• Operated by Julf Helsingius
• 70,000 registered users 10,000 messages/day
• February 1995 Church of Scientology demands the
  True Name of a nym an144108_at_anon.penet.fi
• Revealed on February 8 to belong to
  tc_at_alumni.caltech.edu under order from Finish
  Court
• (Information applied to the Finish court had
  apparently been somewhat misleading)
• August 30 After second court case,
  anon.penet.fi shut down
• full details at www.xs4all.nl/kspaink/cos/rnewman
  /anon/penet.html

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Craigs List
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Key features of an anonymous remailer

• Strips identity from messages passing through
• Provides mapping of nyms to true names
• But only if replies are important
• Optional
• Mixing - only if traffic in and out is observable
• Encryption Prevents intermediaries from knowing
  whats going on.

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Freedom / Onion Routing
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Web Caches Less Sophisticated, but easier to
use

• No special software to install support for
  caches is already built in.
• Can work both ways a cache can also monitor you.

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Web Caches
cache-ntc-ah12.proxy.aol.com - -
10/May/2003224731 -0400 "GET
/clips/1999.TR.LCS35-FountainOfIdeas.pdf
HTTP/1.0" 200 65536 "http//aolsearch.aol.com/aol/
search?queryfountainideaspage2" "Mozilla/4.0
(compatible MSIE 6.0 AOL 7.0 Windows NT 5.1
.NET CLR 1.0.3705) cache-ntc-ah12.proxy.aol.com
- - 10/May/2003224739 -0400 "GET
/clips/1999.TR.LCS35-FountainOfIdeas.pdf
HTTP/1.1" 206 688128 "-" "Mozilla/4.0
(compatible MSIE 6.0 AOL 7.0 Windows NT 5.1
.NET CLR 1.0.3705) cache-ntc-ah12.proxy.aol.com
- - 10/May/2003224744 -0400 "GET
/clips/1999.TR.LCS35-FountainOfIdeas.pdf
HTTP/1.1" 206 1024 "-" "Mozilla/4.0 (compatible
MSIE 6.0 AOL 7.0 Windows NT 5.1 .NET CLR
1.0.3705) cache-ntc-ah12.proxy.aol.com - -
10/May/2003224747 -0400 "GET
/clips/1999.TR.LCS35-FountainOfIdeas.pdf
HTTP/1.1" 206 75 "-" "Mozilla/4.0 (compatible
MSIE 6.0 AOL 7.0 Windows NT 5.1 .NET CLR
1.0.3705)
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Cache with anonymity
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Anonymizer
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Anonymizer.com rewrites URLs
lttd width90 style'backgroundaqua
text-aligncenter fontbold
font-familyArial'gt lta href'http//anon.f
ree.anonymizer.com/http//www.simson.net/photos.ph
p' title'Photos by and of Simson Garfinkel'gt
Photos lt/agt lt/tdgt lttd width90
style'backgroundlime
text-aligncenter fontbold font-familyArial'gt
lta href'http//anon.free.anonymizer.com/h
ttp//www.simson.net/pubs.php' title'Publications
, both academic and journalistic.'gt Pubs lt/agt
lt/tdgt lttd width90 style'backgroundmagenta
text-aligncenter
fontbold font-familyArial'gt lta
href'http//anon.free.anonymizer.com/http//www.s
imson.net/projects.php' title'Current projects'gt
Projects lt/agt lt/tdgt
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Open Proxy

• Like a cache, but no cache!
• No logs (usually)
• Anybody running an open proxy server
• Also used by bad guys

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Unresolved Issues

• How do you buy a book anonymously?

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Anonymous Publishing Services

• anon.penet.fi was really about the right to
  anonymous publication on Usenet (1996)
• The Eternity Service
• Ross J. Anderson
• http//www.cl.cam.ac.uk/users/rja14/eternity/etern
  ity.html
• Publius
• http//www.freehaven.net/anonbib/cache/publius.pdf
  
• Waldman, Rubin Cranor
• Free Haven
• KaZaA?

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Key Items Required for Anonymous Publishing
Service

• Server Management
• Naming of Documents
• Publishing
• Updating
• Deleting
• Indexing
• Payment

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Private Messaging

• PGP first generation
• Hush Mail web based
• The Martus Project application specific
• Groove
• Disappearing Ink (Omniva) Deletion
• c.f. Microsoft Rights Management System

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PGP

• Add-on
• Plug-in
• S/MIME vs. OpenPGP
• Political Baggage

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Hush Mail

• Second-generation
• Web-based
• Java Crypto Client

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Hush Mail
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Hush Mail
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Hush Mail
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Hush Mail
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Hush Mail Interface
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HushMail Diagram
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Matrus

• Closed system for filing human rights reports
• Oriented around bulletins
• Lots of clever ideas

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Martus Login

• Screen-based keyboard to defeat keyboard sniffers.

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Martus Bulletins

• Designed to be easily created, easily searched
• Based on 10 years of research by Patrick Ball

http//dir.salon.com/tech/col/garf/2000/09/08/patr
ick_ball/index.html
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Martus Design

• All information kept in an encrypted database

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Groove Virtual Office

• Peer-to-Peer
• Encrypted Space and Communications
• Messaging
• Future unclear

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Disappearing Ink / Omniva

• Self-destructing email for people who want to use
  it.
• Why bother? Because its hard to delete things

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Email gets copies a lot
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Microsoft Rights Management System

• Like Dissappearing Ink, but you need to have
  permission to get the key
• Main use Preventing forwarding of Microsoft Word
  documents to outside of an organization
• Built into Office 2003

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References

• EPIC Online Guide to Privacy Protecting tools
• http//www.epic.org/privacy/tools.html