Quiz
5 PETS for privacy
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Questions in this quiz (32)
1Protecting Netflix ratings from other users using privacy settings can be seen as social privacy.
- ATrue
- BFalse
2Using TLS to encryption ur communications with the email server can be seen as anti-surveillance privacy.
- ATrue
- BFalse
3Privacy as control aims to hide as much info as possible from the provider.
- ATrue
- BFalse
4A privacy technology that requires more than one entity to decrypt data follows the confidentiality paradigm.
- ATrue
- BFalse
5Privacy is a security problem.
- ATrue
- BFalse
6PETS = P[blank_start]rivacy[blank_end] E[blank_start]nhancing[blank_end] T[blank_start]echnologie[blank_end]s
2 dimensions:
1) Privacy p[blank_start]aradigm[blank_end] : how privacy is defined
2) A[blank_start]dversarial[blank_end] models: who defines the problem & what are the goals- Arivacy
- Bnhancing
- Cechnologie
- Daradigm
- Edversarial
7Privacy paradigm 1: Privacy as c[blank_start]onfidentiality[blank_end]
Privacy's definition in this paradigm:
1) [blank_start]Minimize[blank_end] data disclosure : data [blank_start]encryption[blank_end] in transit / storage, [blank_start]homomorphic[blank_end] encryption to compute when encrypted, [blank_start]obfuscate[blank_end] (perturb, generalise)
2) [blank_start]Distributed[blank_end] trust: secret sharing, [blank_start]multiparty[blank_end] computation
3) Rely/ require [blank_start]open[blank_end] source- Aonfidentiality
- BMinimize
- Cencryption
- Dhomomorphic
- Eobfuscate
- FDistributed
- Gmultiparty
- Hopen
8Privacy paradigm 2: Privacy as c[blank_start]ontrol[blank_end]
Privacy in this paradigm:
1) User [blank_start]participation[blank_end]: let user decide how data will be shared
> privacy [blank_start]settings[blank_end], privacy [blank_start]policy[blank_end] languages
2) T[blank_start]ransparen[blank_end]cy and a[blank_start]ccountabilit[blank_end]y: let user know how data is used, and who is responsible
> secure [blank_start]log[blank_end]ging
3) Organisational c[blank_start]omplianc[blank_end]e: General data protection regulation (GDPR)- Aontrol
- Bparticipation
- Csettings
- Dpolicy
- Eransparen
- Fccountabilit
- Glog
- Homplianc
9Privacy paradigm 3: Privacy as P[blank_start]ractice[blank_end]
Privacy definition in this paradigm & its PETS:
1) Improve user [blank_start]agency[blank_end]: help user ne[blank_start]gotiat[blank_end]e privacy
2) Aid [blank_start]decision[blank_end] making ad [blank_start]transparency[blank_end] of social impact: help users u[blank_start]nderstan[blank_end]d consequences of their actions
3) Privacy as [blank_start]collective[blank_end] practice: help identify b[blank_start]es[blank_end]t practice for a group of users
PETS for all 3:
> c[blank_start]ontextu[blank_end]al feedback (privacy mirrors, preview)
> recommenders for configuration
> privacy [blank_start]nudge[blank_end]s
- Aractice
- Bagency
- Cdecision
- Dtransparency
- Ecollective
- Fnderstan
- Ges
- Hgotiat
- Iontextu
- Jnudge
10Adversarial model 1: PETS for [blank_start]social[blank_end] privacy
Concern: privacy problem is defined by [blank_start]users[blank_end]
eg “My parents discovered I'm gay” / “My boss knows I am looking for other job”
Goal: Do not [blank_start]surprise[blank_end] the user
1) support [blank_start]decision[blank_end] making
2) help [blank_start]identify[blank_end] actions that [blank_start]impact[blank_end]
using: [blank_start]contextual[blank_end] feedback, easy defaults, privacy [blank_start]nudge[blank_end]s
Limitation: only protects from other users, not the trusted [blank_start]service[blank_end] [blank_start]provider[blank_end]!- Aservice
- Bprovider
- Ccontextual
- Dnudge
- Esocial
- Fusers
- Gsurprise
- Hdecision
- Iidentify
- Jimpact
11Adversarial model 2 - PETS for [blank_start]institutional[blank_end] privacy
Concerns - Privacy problem defined by [blank_start]legislation[blank_end]
-> Data should not be collected without user [blank_start]consent[blank_end] or processed for illegitimate uses
-> Data should be secured: co[blank_start]rrect[blank_end], in[blank_start]tegrity[blank_end], de[blank_start]letion[blank_end]
** different countries has different definitions of private data
Goals: [blank_start]Compliance[blank_end] with data protection principles
> [blank_start]informed[blank_end] consent
> purpose [blank_start]limitation[blank_end]
> subject [blank_start]access[blank_end] rights
> data [blank_start]minimisation[blank_end]
> Preserving the [blank_start]security[blank_end] of data: Auditability and accountability
Limitations: Assumes:
1) collection and processing by organisations is ne[blank_start]cessary[blank_end]
> organisations are trusted & honest
> no technical protection of data
2) Focus on [blank_start]limitation[blank_end] of misuses, not on [blank_start]collection[blank_end]
3) Tr[blank_start]ansparen[blank_end]cy
- Ainstitutional
- Blegislation
- Cconsent
- Drrect
- Etegrity
- Fletion
- GCompliance
- Hinformed
- Ilimitation
- Jaccess
- Kminimisation
- Lsecurity
- Mcessary
- Nlimitation
- Ocollection
- Pansparen
12Adversarial model 3: PETS for [blank_start]anti[blank_end]-[blank_start]surveillance[blank_end] privacy
Concerns: the privacy problem is defined by [blank_start]security[blank_end] [blank_start]expert[blank_end]s
> The adversary is [blank_start]anybody[blank_end]
> Concerned about censorship, freedom of speech, surveillance
Goal: Minimize..
1) [blank_start]disclosure[blank_end] of implicit / explicit personal [blank_start]inf[blank_end]o to anyone
>> end-to-[blank_start]end[blank_end] [blank_start]encryption[blank_end]
>> anonymity: t[blank_start]o[blank_end]r, mixnets
>> obfuscation: [blank_start]differential[blank_end] privacy, hiding, generalization
2) [blank_start]trust[blank_end] to others
> [blank_start]private[blank_end] information retrieval
> anonymous aut[blank_start]hentication[blank_end]
> blind [blank_start]signature[blank_end]s
> [blank_start]multiparty[blank_end] computation
Limitations:
1) Privacy-preserving designs are n[blank_start]arrow[blank_end] – difficult to create “general purpose privacy”
> Difficult to combine
> Difficult to ev[blank_start]olve[blank_end] - agile paradigm
2) [blank_start]Usa[blank_end]bility problems both for developers and users
> how to code this?
> [blank_start]perfo[blank_end]rmance down
3) Lack of [blank_start]incenti[blank_end]ves:
> industry will lose the data
> Governments: national security, fraud detection...- Aanti
- Bsurveillance
- Csecurity
- Dexpert
- Eanybody
- Fdisclosure
- Ginf
- Hend
- Iencryption
- Jo
- Kdifferential
- Ltrust
- Mprivate
- Nhentication
- Osignature
- Pmultiparty
- Qarrow
- Rolve
- SUsa
- Tperfo
- Uincenti
13The application gathers the recommendations from the students and then: lets other students see each other recommendations, and lets the bars see the student recommendations so that they can offer discounts to students that give good ratings.
Adversaries: [blank_start]other[blank_end] [blank_start]student[blank_end]s, [blank_start]owner[blank_end]s, [blank_start]cloud[blank_end] provider
They can see: [blank_start]every[blank_end]thing- Acloud
- Bowner
- Cother
- Dstudent
- Eevery
14The application gathers the recommendations from the students and then: lets other students and the restaurant owners see the average rating for a restaurant.
Adversaries: [blank_start]other[blank_end] [blank_start]student[blank_end]s, [blank_start]owner[blank_end]s, [blank_start]cloud[blank_end] provider
They can see: [blank_start]student[blank_end]s and cloud [blank_start]owner[blank_end]s cannot learn students behavior anymore; The Cloud [blank_start]provider[blank_end] still can see everything and learn student behavior and preferences- Aother
- Bstudent
- Cowner
- Dcloud
- Estudent
- Fowner
- Gprovider
15What kind of privacy for each:
> You want to protect the students social network (who is friends with whom) from the students they do not know
PET for [blank_start]social[blank_end] privacy (access control) => Privacy as [blank_start]control[blank_end]
> You do not want the bar owners to learn which bar each student has visited, only the aggregates
PET for [blank_start]social[blank_end] privacy (access control) => Privacy as [blank_start]control[blank_end]
> You do not want the cloud provider to learn what students connect
[blank_start]Anti-surveillance[blank_end] PET for [blank_start]social[blank_end] privacy (anonymous communications) => Privacy as [blank_start]confidentiality[blank_end]
> You want the students to be able to evaluate how much other application users know about them
PET for [blank_start]social[blank_end] privacy (privacy mirrors) => Privacy as [blank_start]practice[blank_end]- Asocial
- Bcontrol
- Ccontrol
- Dsocial
- EAnti-surveillance
- Fsocial
- Gconfidentiality
- Hsocial
- Ipractice
16Technical goals of anti-surveillance PETs: [blank_start]pseudonymity[blank_end]
eg. persistent random id, hashed id, emails, pseudo-id, quasi-id
- Apseudonymity
17Technical goals of anti-surveillance PETs: [blank_start]anonymity[blank_end]
> decouple [blank_start]action[blank_end] from [blank_start]identity[blank_end]!
> hiding: who is...
....the reader of a web page, the person accessing a service
...the sender of an email, the writer of a text
...the person to whom an entry in a database relates
...the person present in a physical location
- Aaction
- Bidentity
- Canonymity
18Technical goals of anti-surveillance PETs: [blank_start]unlinkability[blank_end]
> decouple [blank_start]2 actions[blank_end] from [blank_start]1 user[blank_end]!
> hiding: Two...
... anonymous letters written by the same person
... web page visits by the same user
... entries in a databases related to the same person
... two people related by a friendship link
... same person spotted in two locations- Aunlinkability
- B2 actions
- C1 user
19Technical goals of anti-surveillance PETs: [blank_start]unobservability[blank_end]
> decouple [blank_start]observation[blank_end] from [blank_start]action existence[blank_end]!
> hiding:
...whether someone is accessing a web page
...whether a message is being sent
...whether an entry in a database corresponds to a real person
...whether someone or no one is in a given location- Aunobservability
- Bobservation
- Caction existence
20Technical goals of anti-surveillance PETs: [blank_start]plausible[blank_end] [blank_start]deniability[blank_end]
> decouple [blank_start]observation[blank_end] from [blank_start]true action[blank_end]!
> Not possible to prove ...
... that a person has hidden information in a computer
... that someone has the combination of a safe
... that a person has been in a place at a certain point in time
... that a database record belongs to a person- Aplausible
- Bdeniability
- Ctrue action
- Dobservation
21However, ______ is breakable using a probabilistic analysis
- Aconfidentiality
- Bpseudonimity
- Canonimity
- Dunlinkability
- Eunobservability
- Fplausible deniability
22Systematic privacy evaluation:

- Aidentify
- Baction A
- Caction B
- Dreal action
- Efake
- Freal
- Gobfuscated
23Systematic privacy evaluation
1) Model the privacy-preserving mechanism as a [blank_start]probabilis[blank_end]tic transformation
> What is the probability that, given an input the privacy mechanism returns a given output
2) Determine what the [blank_start]adversary[blank_end] will see
> Threat model: who is the adversary? what is the “ob[blank_start]servation[blank_end]”? what is her p[blank_start]rior[blank_end] knowledge?
3) “Invert” the mechanism as the adversary would do
> Always assume the adversary knows the me[blank_start]chanism[blank_end] and would try to undo its effect
4) Evaluate property after in[blank_start]version[blank_end]
> This is the real pr[blank_start]obability[blank_end] the adversary can compute
5) Measure
> Not trivial!- Aprobabilis
- Badversary
- Cservation
- Drior
- Echanism
- Fversion
- Gobability
24Measuring privacy:
> [blank_start]Correctness[blank_end]: given the distribution, what is the probability that the adversary does not guess correctly?
> [blank_start]Uncertainty[blank_end]: given the distribution, what is the uncertainty of the adversary on the answer?
> [blank_start]Accuracy[blank_end]: given the distribution, and a guess, how certain is the adversary of his inference?
> [blank_start]Differential[blank_end] [blank_start]privacy[blank_end]-based: given the observation what is the bound on the information the adversary can gain- ACorrectness
- BUncertainty
- CAccuracy
- DDifferential
- Eprivacy
25What privacy properties are being achieved?
A. A user accesses a web three days in a row, and the web cannot recognize it is the same user- AAnonimity
- BUnlinkability
- CUnobservability
- DPlausible deniability
- EPseudonymity
26What privacy properties are being achieved?
B. A user has a program in its computer that publishes Tweets automatically. Twitter cannot prove that a given Tweet was made by the user- AAnonymity
- BUnlinkability
- CUnobservability
- DPlausible deniability
- EPseudonimity
27 what privacy properties are being achieved?
C. A user uses her university account for accessing university services and her Gmail account to access Netflix.- AUnlikability
- BUnobservability
- CPseudonimity
- DAnonymity
- EPlausible deniability
28what privacy properties are being achieved?
A user accesses a newspaper website using a proxy, the newspaper can only see the proxy
IP address if she is the only user behind the proxy.- APseudonymity
- BAnonymity
- CUnlinkability
- DUnobservability
- EPlausible deniability
29what privacy properties are being achieved?
D. A user accesses a newspaper website using a proxy, the newspaper can only see the proxy
IP address if there are several users behind the proxy.- APseudonymity
- BPlausible deniability
- CUnlinkability
- DUnobservability
- EAnonymity
30Which of the 2 system provides better unlinkability between a student and a comment?
A. a system that always mixes the feedback from two students before presenting it to the professor (i.e., comment from student Bob appears sent by student Alice and vice versa)
B. a system that with 50% of the time forwards the comment of a student and 50% of the time forwards a fake comment- AA
- BB
31PETS for data anonymization:
Produce a dataset that preserves the utility of the original dataset without leaking information about individuals
- Aquasi-identifiers
- Blink
- Canonymity
32What property/properties Alice enjoys
- if she uses one-time credentials to users login in a website (imagine a random number that can only be shown once, like a ticket to the cinema)
- with respect to the website? [blank_start]Anonymity[blank_end], [blank_start]Unlinkability[blank_end]
- with respect to the credential issuer? If the credential is obtained in person: [blank_start]none[blank_end]. If the credential is
obtained online, [blank_start]pseudonymity[blank_end].
- regarding email receivers, if every time she wants to send an email she ask one of our friends to send it for us
- if each friend sends at most one email - [blank_start]Anonymity[blank_end]
- if friends can send more than one email - [blank_start]Pseudonymity[blank_end]- AAnonymity
- BUnlinkability
- Cnone
- Dpseudonymity
- EAnonymity
- FPseudonymity
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- - Information security (5 PETS for privacy) Quiz on 5 PETS for privacy, created by Yawen Hou on 10/06/2019.
- Author
- Yawen Hou
- Language
- English
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