Page 59 - Trust in ICT 2017

Trust in ICT 1

values and metrics with continuous values. Brondsema and Schamp [41] model and represent trust
and distrust in a similar fashion using continuous values. Having continuous range of values allows
easier propagation of trust values, along the edges on the networks, using inference mechanisms.
They represent the relationship as the class and main concept of the ontology. Each relation is
directed from source (trustor) to sink (trustee). Properties of relations are wrapped under the
concept of trust item. The most important feature of this work is, like Jennifer Golbeck’s ontology,
they have incorporated the notion of “Topical trust” in their ontology. It is used as an attribute and
property, which allows to state different features and properties of a relationship. Trust topics and
trust values are stated as properties of the trust relationship.
In order to describe trust relationships, an ontology is presented using Resource Description Framework
(RDF), which in turn eases extending the FOAF vocabulary and profiles. Using the RDF properties, and taking
into account that relationship can be described using FOAF vocabulary and ontology, then trust relationships
can be described using trust ontology. Other technology that has been integrated is Web-of-Trust, which is
used to describe Web-of-Trust resources such as key fingerprints, signature and signing capabilities and
identity assurance. Ontology’s RDF schema is made of 2 classes or concepts and 5 attributes or properties.
As mentioned, the primary concept is Relationship between two people. Like most trust ontologies, there
are two properties that are required for every Relationship, and they form the endpoints of every
relationship; trustor and trusted using FOAF vocabulary, both trustor and trusted have foaf:Person objects
as their targets.

6.5 Trust Provisioning in System Domain
6.5.1 System Lifecycle

Trust can be used for software development. It is one of the trust provisioning strategies in the perspective
of system.

OPTET, an EU-funded project under the 7th Framework Programme, adopts a unique approach designed to
cover all relevant trust aspects of a software development and operation life cycle. The project has developed
a unified cross-disciplinary model of trust and trustworthiness, which is used to represent and quantify the
trust of all stakeholders and the trustworthiness of socio-technical system.

2
Figure 8 – The OPTET Lifecycle
OPTET plans to cover the whole life cycle of trustworthy ICT systems (from requirements right through to
production, via the stages of implementation, validation and integration), with a multidisciplinary approach
and by taking into account the drivers of stakeholders’ trust. Thus, it defines its own engineering-based
development approach which describes different phases for the trust and trustworthiness attributes lifecycle
in a custom software development methodology are described in Figure 25. This OPTET lifecycle identifies
additional activities to the typical development lifecycle processes and verifies that trust and trustworthiness
are adequately addressed, both at design time, deployment time and runtime.

2 OPTET project website: http://www.optet.eu/about/

51