Trust and Reputation Management in an Web-

Enhanced World

Zhaoyuan Zhang Email: zz2198@columbia.edu

Introduction of trust and reputation management1

2

3

Preview

Models for trust and reputation management

Utilization of the models

Why trust and reputation management?

Emails

E-Commerce

Cloud Computing

Gain knowledge about unknown web services

More efficient investments

Helpful in making decisions

Less risks

REASONSREASONS

Agents

Trusting agent:

“An entity who has faith or belief in another entity in a given context and a given time slot” （ Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 27. Johns Wiley & Sons; 2006.）

Trusted agent:

“An entity in whom faith or belief has been placed by another entity in a given context and at a given time slot”

（ Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 28. Johns Wiley & Sons; 2006.）

A time slot is “a period of time … defined as the breadth or duration of time over which the trust value is collected”Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 40. Johns Wiley & Sons; 2006

Trust is “defined as the belief the trusting agent has in the service provider’s willingness and capability to deliver a

mutually agreed service in a given context and in a given time slot”.

(Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 27. Johns Wiley & Sons; 2006.)

Trust Recommendation

Trust recommendation is “a method that helps to form a trust relationship by deriving the initial trust value, also known as reputation based on references or recommendations collected from other parties”.

(Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 40. Johns Wiley & Sons; 2006.)

Models for Trust and Reputation Management

Deterministic Approach

Bayesian Approach

Fuzzy Approach

Trust Models

Deterministic Approach

Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Page: 251. Johns Wiley & Sons; 2006.

Deterministic Approach

Two agents: Trusting agent: web service user Trusted agent: one or several third party agents

Trusted agent gives the trust recommendation

Trusting agent analyzes the trust recommendation from trusted agents

Analysis is based on a period of time

A negative historical experience

has a value of 0

Bayesian Approach

Bayesian Theorem

Use a web service’s historical performance to predict the future performance

A positive historical experience

has a value of 1 Use historical trust value (history) of a web service as the

condition:

Fuzzy Approach

• Reliability• Availability• Security

Define fuzzy sets of expected results of a web service from different criteria:

Use a web service’s historical performance statistics

For each record of the history, compare it from each aspect with the defined result sets

.

Amazon’s Mechanism“Our very best sellers have a close to 0% Negative Feedback Rate… A 0-2% negative feedback rate indicates a good performance of a seller. While a negative rate of greater than 5% means there is some problem with the business practice…The feedbacks are 12-month based…”

http://www.amazon.com/gp/help/customer/display.html?nodeId=1161284&#good

Utilization of the models

Amazon’s Mechanism

Historical trust statistics

Fuzzy sets indicating different levels of potential performance results

Trust value is based on a time slot

Combination of different models

Conclusion

Introduction of trust and reputation management• Why trust management?• Definition of trusting agents, trusted agents, time slot, trust, trust

recommendations.

Models for trust and reputation management• Deterministic Approach: trust recommendation• Bayesian Approach: historical trust value statistics• Fuzzy Approach: fuzzy sets, historical trust value statistics

Utilization of the models Combination of different models

References

Chang, Elizabeth. Trust and Reputation for Service-Oriented Environments Technologies for Building Business Intelligence and Consumer Confidence. Johns Wiley & Sons; 2006.

M.wojcik. H.S. Venter. J.H.P. Eloff. Trust Model Evaluation Criteria: A Detailed Analysis of Trust Evaluation. 2008

Agudo, Isaac. Fernandez-Gago, Carmen. Lopez, Javier. A Model for Trust Metrics Analysis.

Zhu, Manling. Jin, Zhi. Trust Analysis of Web Services Based on a Trust Ontology. 2007.

Machala, Daniel. E-Commerce Trust Metrics and Models. Xeroxr Research and

Technology Receiving Amazon.com Feedbacks from Buyers.

http://www.amazon.com/gp/help/customer/display.html?nodeId=1161284&#good Nefti, Samia. Meziane, Farid. Kasiran, Khairudin. A Fuzzy Trust Model for E-

Commerce. Li, Wenjuan. Ping, Lingdi. Trust Model to Enhance Security and Interoperability

of Cloud Environment. 2009 Thrope, Sean. Modeling a Trust Cloud Context. 2010.

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