Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue...
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Transcript of Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue...
![Page 1: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/1.jpg)
Privacy on the Web
Gertzman Lora
Krakov Lena
![Page 2: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/2.jpg)
Why privacy?• Privacy is the number one consumer issue
facing the internet.
• An eavesdropper (server, service provider or a private person) can reveal surfer’s identity, profile etc.
• The computer security community has concentrated on improving user privacy by hiding his identifiable tracks on the WEB, thus assuring his anonymity while surfing.
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Anonymity as a solution
Rough definition: A communicates
anonymously with B, if B doesn’t know A’s
identity, and if A’s and B’s communication
can’t be linked together by someone who has
an overview on the global network.
Sometimes B is allowed to know A’s identity,
but both sides want to hide their
communication from outsiders.
![Page 4: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/4.jpg)
Anonymity properties
1. Anonymity type (sender / receiver anonymity)
2. Adversaries (web server, eavesdropper)
3. Degree of anonymity (ranges from absolute privacy to provably exposed)
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Anonymity as a solution (cont.)
• Disadvantage: can be misused by criminals or people with malicious intentions (spam e-mail, money laundering).
• Providing anonymity on the internet isn’t trivial.
• We’ll present 4 solutions: • Anonymizer
• Crowds
• Onion Routing
• The new privacy model
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Anonymizer
• Popular tool for anonymizing web communication.
• Web site that serves as a mediator between the client and the server.
• Used as web proxy, that strips identifying data and forwards the request.
• Similar mechanism is the LPWA (Lucent Personalized Web Assistant)
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How anonymizer works
• User requests URL via the browser.
• The request sent to the anonymizer.
• Anonymizer submits the URL to end server.
• Server replies to anonymizer.
• Anonymizer sends the response to the user.
![Page 8: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/8.jpg)
Advantages & disadvantages
Advantages:
• Simple.
• Doesn’t need wide bandwidth.
• Quick.
Disadvantages:
• The sender- anonymizer link isn’t secure.
• The user must trust the anonymizer.
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Crowds
• An innovative way to become an invisible user is simply to get lost in the crowds. After all, anonymity loves company.
• This is an anonymity agent developed by AT&T labs.
• The goal: anonymous browsing, so that user data and retrieved info are hidden from web servers and other parties.
![Page 10: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/10.jpg)
How crowds works
• Collecting web users into geographically diverse group called “crowd”.
• User represented by a process on his local machine called “jondo”.
• The jondo engages in a protocol to join the crowd and exchanging data with the other members.
• Now jondo can employ the crowd to issue requests to web servers.
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How crowds works (cont.)
• User requests URL via the browser.
• The HTTP request being sent to the jondo.
• Jondo randomly chooses another crowd member and sends the request to him.
• The new member chooses to forward or to submit the request (pf>0.5), creating “path”.
• The request is submitted to the end server.
• The answer is sent along the same path.
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How crowds works (cont.)
• Subsequent requests initiated by the same jondo follow the same path, even if they have different destinations.
• Each jondo knows his predecessor and successor.
• Path is changed only when jondo fails or a new jondo joins the crowd.
• All communication between jondos is encrypted, by key shared between them.
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Advantages & disadvantages
Advantages:• End server obtains
no data about the request initiator.
• Each crowd member is probably innocent.
• The jondos on the path don’t know the initiator
Disadvantages:• Message content isn’t protected.• Increasing retrieval time & bandwidth.
• Mobile code allows to circumvent crowds.• Submitting jondo’s IP may be recorded by the end server.
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Onion Routing
• It’s an infrastructure for private communication over public network.
• Provides anonymous connection that are strongly resistant to eavesdropping and traffic analysis.
• An onion is a layered data structure, treated by onion routers.
• Users submit layered encrypted data and at each pass through each onion router one layer is removed.
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How onion routing works
• The network consists of a number of onion routers and is accessed via series of proxies.
• Data is sent by the user through a path of onion routers, determined by an onion.
• The onion is encrypted with the public key of the onion router to which it is sent. It contains the next hop info, key seed material and embedded onion.
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How onion routing works (cont.)
• Data movement from an initiating client to responding server:
Client Data stream Server
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How onion routing works (cont.)
Four phases in an onion routing system:1. Network setup (establishes connections
between OR).2. Connection setup (establishes anonymous
connections through the OR network).3. Data movement over an anonymous
connection.4. Destruction and cleanup of anonymous
connection.
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How onion routing works (cont.)
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Advantages & disadvantagesAdvantages:• Independent from
the actual application.
• Resistant to both eavesdropping and traffic analysis.
• Almost real time.
Disadvantages:
•Sender-first OR and last OR-receiver not anonymity protected.
•Limits traffic delay and therefore limits OR mixing properties.
•Connection bandwidth
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A new privacy model
• This model was developed in BG University(2002).
• Designed for preserving users’ privacy while allowing them to identify themselves.
• Based on generation of faked transactions.
• Researchers are still planning to evaluate the effectiveness of the model.
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A new privacy model(cont.)
• A User Transaction- an access to a web page from the user computer.
• Internal user profile (IUP)- constructed inside the user’s computer and based on the content of pages the user accesses.
• External user profile (EUP)- based on the data flowing from the Web to the user’s computer.
In this model the EUP is different from IUP.
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A new privacy model(cont.)
• The new model uses vector space model based on the representation of documents and profiles by a vector of significant weighted terms.
d=(w1,w2,…,wn)
wi- weight of term i in document d.
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A new privacy model(cont.)
• A new document(candidate) is considered relevant to user if the vector d is similar to the user profile.
• Cosine measure: the cos of the angle between two vectors
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How the new model works
Three main components:
1. Browser Monitor
2. Transaction Generator
3. Profile Meter
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back
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Browser Monitor
• Input - user transactions• Output - vector of weighted terms for each
trans’ result sent to the Profile Meter. - trigger to Transaction Generator.• Functionality- while the user is surfing the
Web, BM generates a vector of weighted terms, , at time stamp . The trigger that sent indicates a completion of user’s trans’.
VU
tU t
U
To figure
![Page 27: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/27.jpg)
Transaction Generator
• Input - a trigger from the Browser Monitor
- set of terms from an internal DB
- IUP from the Profile Meter
- faked transaction results(Web pages)
• Output- vector of weighted terms for each faked trans’ sent to the Profile Meter.
To figure
![Page 28: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/28.jpg)
Transaction Generator(cont.)
• Functionality - constructs the “faked trans’ query string”.- randomly accesses selected pages from results
to the query.- generates faked trans’. User calibrates the
average number of faked trans’ per user trans’- .
- builds a vector of term weights for each of faked trans’, , at time stamp .
T r
VT
tT t
T
To figure
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Profile Meter
• Input - vector , from the BM
- vector , from the TG
- parameters , from the user
• Output - IUP to TG
- current degree of privacy of the user
VT
tT
VU
tU
T r rP
To figure
![Page 30: Privacy on the Web Gertzman Lora Krakov Lena. Why privacy? Privacy is the number one consumer issue facing the internet. An eavesdropper (server, service.](https://reader031.fdocuments.in/reader031/viewer/2022032704/56649d4c5503460f94a2a073/html5/thumbnails/30.jpg)
Profile Meter(cont.)
• Functionality
- generates the IUP ( )
- generates the FUP( ), faked trans’ profile at time stamp :
- generates the EUP(t), combining IUP and FUP into one vector
- computes the Privacy Measure
tU
tT
tT
To PM figure
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Computing the Privacy Measure
• Whenever the IUP or the EUP changes, PM computes the similarity between the profiles by finding the cos of the angle between the vectors:
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The Profile Meter tasks
back
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Advantages & disadvantages
Advantages:
•Enables the user to identify himself while preserving his privacy
•Enables the user to calibrate him privacy
Disadvantages:
•Communication bandwidth towards the Internet
•Works around MS Internet Explorer only
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Prototype System
• The system consists of a smart agent installed in the user computer
• The system is built around the MS Internet Explorer
• The Transaction Generator and the Profile Meter are written using Borland C++ Builder
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Future Research
• The effect of different values of on similarity
• The effect of different values of on system performance
T r
rP
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The End