Page 64 - Trust in ICT 2017

1 Trust in ICT

trust, community trust also needs to be considered. For SCP relationships, trust as a cross-domain
relationship is needed, taking into consideration coexistence, connectivity, interactivity and spatio-temporal
situations between vertical layers.

Human-to- Object-to-
Human Trust Object Trust
Humans Objects

Trustworthy Social-Cyber-Physical Infrastructure

Human-to-
Humans Object Trust Objects

Figure 13 – Trust relationships in a trustworthy social-cyber-physical infrastructure

7.3 Trust Components and Platform Architecture
The choice between centralized and decentralized trust management system must be taken into account,
depending on trust model and trust-related information processing. In the centralized approach, the trust
information can be computed on demand, whenever an entity needs to rely on its cooperative entities, and
delivered to the requesting entity at that moment. On the other hand, the distributed approach computes
trust on a regular basis and be propagated throughout the topology. An entity itself in the large scale network
like social IoT possibly lacks of knowledge to evaluate trust. It certainly needs help from others such as trusted
authorities. Moreover, a real-time trust data flow would result in communication overhead, detrimental to
network performance as well as to constrained entities battery life. However, the traditional strategies for
centralized system are difficult to suit for solving trust issues of a large scale distributed network like social
IoT because of their poor scalability as well as center-dependence leading to single point of failure. Thus, it
is considered edge or fog computing architecture [49] which could be considered as semi-distributed system.

In order to deploy the trust service platform, besides the Reputation System, it is necessary to define and
incorporate three new basic components to the ICT ecosystem: Trust Agent, Trust Broker and Trust Analysis
and Management. The following briefly presents these components by describing their responsibilities and
interactions in the system (See Figure 14).

56