wp5: identity management and reputation framework for trusted negotiation

6th November 2007 1st ONE Review, Brussels1

WP5: Identity Management and Reputation Framework for Trusted

Negotiation

Partners: CN, SN, WIT, FBK, UdG, UNISG

Speaker: Mihaela Ion (CN)


WP Overview

Core security primitives: platform independent and transparent to underlying crypto protocols and mechanisms

Identity management model for automatic processing of user identity information which scales to a decentralized environment

Trust & reputation scheme for P2P or agency-centric recommendations

Security primitives (T5.1)

Identity Management (T5.2)

Rating Agencies (T5.3)

P2P reputation (T5.4)

Trust & Reputation Mgmt

Fig. WP5 tasks and relations between them

Security primitives and identity management functionalities used by all ONE components (WP2, WP3, WP4)

Decision support functionalities to users and WP4


T5.1 Security Primitives: Authentication, Integrity and Confidentiality

Independent from specific cryptographic algorithms and protocols

Allow new algorithms to be plugged in the future: we target evolutionary DEs

Will be deployed as Java APIs on each ONE node providing Web Services integration capabilities

Provided through: username & password, certificates, SSO, digital signatures, SSL/TLS, symmetric and asymmetric encryption and digest

APIs already designed and D5.1 was submitted (task completed as scheduled)


T5.2 Identity Management and PrivacyThe model targets an automated process of identification between

ecosystem entities.

Practical solutions which are clear and easy to adopt and implement by SMEs.

Provide interoperability by convergence between existing identity technologies through SAML (v2.0).

Use of user identity profile: an abstract view of a user’s identity information.

Decentralized identity information is managed through user profiles replicated in a peer-to-peer fashion on trusted nodes.


Main Characteristics of the ModelMain target: decentralized P2P ecosystem domains

All users are equal and there is no hierarchy of DEs

Any peer can be a Credential Provider (CP) or a Service Provider (SP), or both

Each SP has a list of trusted CPs

Each CP has a list of trusted CPs and a list of accepted security tokens

SAML unifies different identity representations that might be used by different SPs

CPs translate from SAML to their SPs security tokens representations and viceversa (e.g. X.509 SAML, SPKI SAML, Kerberos SAML)

Each CP issues certificates to users based on:

Secure tokens issued by the CP itself,

Secure tokens issued by a CP with whom it has a trust relationship, or

User registration information


User ProfileUnified view of a user’s distributed identity information

Encrypted with a master password known only by the user

Replicated encrypted on trusted peers

Downloaded, decrypted and updated on secure memory on user’s side

Obtained using username & password (different from the master password) when logging to the ONE system.


Model Communication Scheme

Browser/Service on another peer

Service Provider Credential Provider

Trust relationship

Requestresource

Authenticationrequest

Authenticationrequest

List of accepted certificates

Certificates

TokenToken

Resource

Public list of acceptedsecurity tokens

Public list of trusted SCPs

Login/Requestprofile

Service Provider

Public list of trusted CPs


Trusted Peer

Encrypteduser profile


Credential Provider

List of issuedcertificates/tokens

ProfileRequest token/certificate

Certificate

112

forwarding

11

12

3

4

5

6

7

8

9

110

111


Service Composition by Proxy Cert

SP1 CP1

SP2 CP2

Trusted Peer

Trust relationship

Trust relationship

Requestservice

Browser/Serviceforwarding

Requestservice Result

Result

PC

PC

11

1233

1415

66

17

Composed service

Profile download

+policies

+policies


T5.3 Trusted Rating Agencies

P2P reputation is subjectiveCertificates issued by rating agencies should be objective and hence

more trustworthy Inspiration from financial rating agenciesDedicated service that could be offered by each ONE nodeEach entity decides on its own to register or not with an agencyEach agency specifies its predefined criteria on which users are

registered (necessary credentials)Agencies across the ONE platform cooperate with each other to

retrieve information about unknown users

Authorization certificates


T5.4 Peer-to-peer ReputationWe model adaptive reputation-based trust: Based on opinions (recommendations) expressed by users about other

users, data, services and nodes (multi-levels)Social networks represented through contacts lists (private - shared

only with contacts)Context-aware trust values: users have different levels of expertise in

different domainsMultidimensional trust: e.g. a service can be rated for availability,

response time, memory usage, result accuracy etc.Bootstrapping:

Make use of trust relations established between users outside the systemAssign higher levels of trust to newcomers based on credentials obtained from

trusted Certification Authorities outside the system


Initial reputation valuesWe use probabilistic values from 0 (no

trust or no information) to 1 (complete trust).

Users provide registration information to the CP of the chosen ONE node including certificates obtained from external CAs

CPs assign initial trust values based on relations with the CAs

Invited users are added to the social network of the inviter which assigns manually a trust value Fig. Internal CPs and external CAs

trust relations


Contacts’ lists and lists of opinionsContacts’ list

Trusted contacts known either from outside or inside the system

Different trust levels attached to each contact: the trust a user has to receive accurate recommendations

List of opinionsBased on direct interactions Each user keeps on his private

MyONE space a history of (recent) experiences (negotiations, transactions) with other users, services, and data.

4-tuples composed by subject, object, keyword and value.


Propagation of opinions across the contacts graph

Users ask their contacts’ opinions about unknown entities

These can further ask their contacts if no information is available

MoleTrust predicts the trust score of source agent on target agent by walking the trust graph starting from the source agent and by propagating trust along edges.

Trust values are weighted by the trust scores of the agents who issued them (as stated in the contacts’ list)

Trust values are relative to the source agent

Fig. Propagation of opinions across the contacts graph


Opinion’s Data Model

Contexts are expressed by user defined keywords (folksonomy)

Simple or complex contexts (e.g. a taxonomy)

Through contexts we model the multidimensional nature of trust

Fig. Generalized Opinion Data Model


Status & Next StepsSecurity primitives

Status: implementation of user authentication with username & password Next steps: implementation of advanced authentication mechanisms (certificates , SSO )

Identity managementStatus: model designed and partially implemented ( simple user registration )Next steps: user profile and transformations, complete the model implementation

Trusted rating agencies Status: Inspiration from financial rating agencies, objective, based on credentials, in line

with the distributed nature of ONE Next steps: design the model

P2P reputation Status: model designedNext steps: draft implementation for simulations and validation, collaboration with WP3

- T3.4 for the replication algorithm of the Distributed Knowledge Base.


Task 5.2 will be extended until month 19, and deliverable D5.4 will be delayed until month 19 and a new milestone will be added at month 15 providing draft implementations. For bugs fixing and software enhancements after the First Trial Iteration additional 4 Months are required, they will be distributed from month 23 to month 26.

Task 5.3 will be extended until month 20 and deliverable D5.3 will be delayed until month 20. The reason for this extension is caused by the delay of the research activities in Phase I.

wp5: identity management and reputation framework for trusted negotiation

Documents