Fine-Grained Trust Assertions for Privacy Management in the Social Semantic Web
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Fine-Grained Trust Assertions for Privacy Management in the Social Semantic Web

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  • Generic privacy settings – does not provide privacy settings for each part of the information SNs do not cater for trust, neither capture trust not even provide users to enter any trust information Assumes that every person in ones social graph has the same trust level Does not provide users to enter trust values for different user lists Cumbersome to manage contacts with respect to trust
  • Unlike the state-of-the art that focuses on 1 social factor and assumes that the users manually provide a trust score
  • We are working with personal subjective trust values Asymmetric, if I give a trust value to a person, it does not mean that person has the same trust value for myself .. Therefore each person calculates personal trust values for people
  • identity of the requester: trust can be asserted from the credentials exchanged through authentication, profile similarity between the user and the requester: trust can be asserted by matching several profile attributes with one another, the relationship type between the user and the requester: trust can be asserted based on the importance of the relationship type, the reputation of the user within a trusted network: trust can be asserted through reputation information asserted from other entities in a Web of Trust, trust based on interactions between the user and the requester: trust can be asserted based on the number of interactions between the user and the requester over a particular period of time.
  • “ the more similar two people were, the greater the trust between them” Attributes such as work place information, interests, projects, connected peers and other profile attributes are compared profile-similarity by calculating the relationship between the sum of matched distinct profile attributes between the user’s profile and the requester’s profile, and the total sum of all the distinct attributes within the user’s profile.

Fine-Grained Trust Assertions for Privacy Management in the Social Semantic Web Fine-Grained Trust Assertions for Privacy Management in the Social Semantic Web Presentation Transcript

  • © Copyright 2011 Digital Enterprise Research Institute. All rights reserved. Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Fine-Grained Trust Assertions for Privacy Management in the Social Semantic Web Owen Sacco, John G. Breslin & Stefan Decker firstname.lastname@deri.org IEEE TrustCom 2013 – Melbourne Australia Tuesday 16th July 2013
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Introduction  Current Social Networks  provide generic privacy settings for sharing information  do not take user’s trust into account
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Introduction In reality, we only share parts of our information to whom we trust
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Research Contribution In this work we focus on: Using various methods to automatically assert fine-grained subjective trust values for different Social Factors to grant or restrict access to personal information
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Use Case 1. Alex sends a request to view John’s personal information 2. Alex is granted access to the information which his trust value (asserted by John) satisfies a trust threshold (assigned by John)  Example: Provide John’s phone number to Alex if he has a trust level of 0.83 Social Web Platforms ... 1 2 Alex John
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Defining Trust In our work trust is defined as: “a person’s subjective belief that another person will act responsibly and will not misuse the information”
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Social Factors  Trust judgments are influenced by Social Factors:  Past interactions with a person  Opinions of a person’s actions  Other people’s opinions  Rumours  Psychological factors impacted over time  Life events  and so forth  These can be hard to compute since the information required is limited and unavailable in Social Networks
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Social Factors  However, we have identified several factors that trust can be asserted from the information available in Social Networks:  Identity  Profile Similarity  Relationship type  Reputation in a Web of Trust  Interactions
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertion Framework Social Web Platforms ... Alex JohnSocial Semantic Web Platform Trust Manager 1 2 1 2 3 5 4 6
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Social Semantic Web
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Model  Trust values are represented in the range of [-1,1]  1 represents absolute trust  0 represents either uncertainty or unknown  -1 represents absolute distrust  Positive values less than 1 represents trust but with an element of uncertainty  This also applies to negative values
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Identity-based Trust  Relies on authentication  The WebID protocol is used as a Single Sign-On Service for Semantic Web applications – WebID provides users to authenticate using FOAF and X.509 certificates over SSL  The subjective trust value is assigned to the requester after s/he authenticates using WebID  1 if successful, -1 if unsuccessful and 0 if aborted  Definition 1: Identity-based Trust Certificate(Cert,R) Profile(RP,R) Verify(Cert,RP)∧ ∧ ∧ AssertedBy(R,U) AssignTrust(IDT,R)⇒
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Profile Similarity-based Trust  Asserting trust based on the similarities between the user profile and the requester  Basic information attributes are not taken into consideration  Attributes such as work place information, interests, connected peers and other profile attributes are compared  Profile similarity-based trust calculation: – denotes profile similarity subjective trust valueτ – m denotes the matched distinct profile attributes between the user’s profile and the requester’s profile – a denotes the user’s distinct profile attributes
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Definition 2: Profile Similarity-based Trust ∀UA(Profile(RP,R) Profile(UP,U)∧ ∧ Contain(RA,RP) Contain(UA,UP) Match(RA,UA)∧ ∧ ∧ AssertedBy(R,U)) AssignTrust(PST,R)⇒  where PST {-1,1}∈
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Relationship-based Trust  The Social Semantic Web provides the user to enter a value of how much s/he trusts that particular relationship type  Definition 3: Relationship-based Trust ∀URT(Profile(UP,U) Contain(URT,UP)∧ ∧ Relationship(R,URT) AssertedBy(R,U)) AssignTrust(RLP,R)∧ ⇒  where RLP {-1,1}∈
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Reputation-based Trust  Consists of a trust value of a user within a Social graph based on all trust values given by other users  Reputation-based trust value is the weighted average value of all trust values given to a user – The user’s trust values assigned within a network – The weights denotes the reputation value of the person that assigned the trust value  Reputation-based trust calculation: – τ denotes reputation trust – w denotes the reputation of the user assigning a subjective trust value to the requester – v denotes the requester’s subjective trust value assigned by a user
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Definition 4: Reputation-based Trust SocialGraph(SG,U) Contain(R,SG) Measure(RV,SG)∧ ∧ ∧ Reputaion(RV,R) AssertedBy(R,U) AssignTrust(RPT,R)∧ ⇒  where RPT {-1,1}∈
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Interactions-based Trust  Consists of users sharing microblog posts, comments, photos, videos, links and other content with their peers  Interactions-based trust calculation: – denotes interactions trust valueτ – r denotes the number of interactions between the requester and the user – u denotes the number of all the user’s interactions in the Social Web platform
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Definition 5: Interactions-based Trust ∀UI(Profile(UP,U) Contain(UI,UP) Interaction(R,UI)∧ ∧ ∧ AssertedBy(R,U)) AssignTrust(INTT,R)⇒  where INTT {-1,1}∈
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertions Model  Aggregating Subjective Trust Values  To assign a fine-grained user’s subjective trust value to a requester  An average of all the subjective trust values of a requester from each social factor assigned by the user  Aggregate subjective trust calculation: – denotes the aggregated subjective trust valueτ – s a subjective trust value asserted based on a social factor
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Trust Assertion Ontology (TAO) http://vocab.deri.ie/tao
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Information Confidentiality http://vocab.deri.ie/ppo
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Implementing Trust Assertions
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Results
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Future Work  To show how this model is useful for other scenarios (for example for Recommender Systems)  To calculate automatically Relationship-based Trust values  To take into account the trust values of Certificate Authorities when calculating Identity-based Trust  To compare our model with other state-of-the-art models
  • Digital Enterprise Research Institute www.deri.ie Enabling Networked Knowledge Thanks! Email: owen.sacco@deri.org