  The next generation of the Internet of Things (IoT) facilitates the
integration of the notion of social networking into smart objects (i.e.,
things) in a bid to establish the social network of interconnected objects.
This integration has led to the evolution of a promising and emerging paradigm
of Social Internet of Things (SIoT), wherein the smart objects act as social
objects and intelligently impersonate the social behaviour similar to that of
humans. These social objects are capable of establishing social relationships
with the other objects in the network and can utilize these relationships for
service discovery. Trust plays a significant role to achieve the common goal of
trustworthy collaboration and cooperation among the objects and provide
systems' credibility and reliability. In SIoT, an untrustworthy object can
disrupt the basic functionality of a service by delivering malicious messages
and adversely affect the quality and reliability of the service. In this
survey, we present a holistic view of trustworthiness management for SIoT. The
essence of trust in various disciplines has been discussed along with the Trust
in SIoT followed by a detailed study on trust management components in SIoT.
Furthermore, we analyzed and compared the trust management schemes by primarily
categorizing them into four groups in terms of their strengths, limitations,
trust management components employed in each of the referred trust management
schemes, and the performance of these studies vis-a-vis numerous trust
evaluation dimensions. Finally, we have discussed the future research
directions of the emerging paradigm of SIoT, particularly for trustworthiness
management in SIoT.
