  5G networks intend to cover user demands through multi-party collaborations
in a secure and trustworthy manner. To this end, marketplaces play a pivotal
role as enablers for network service consumers and infrastructure providers to
offer, negotiate, and purchase 5G resources and services. Nevertheless,
marketplaces often do not ensure trustworthy networking by analyzing the
security and trust of their members and offers. This paper presents a security
and trust framework to enable the selection of reliable third-party providers
based on their history and reputation. In addition, it also introduces a reward
and punishment mechanism to continuously update trust scores according to
security events. Finally, we showcase a real use case in which the security and
trust framework is being applied.
