Over the past few years, cloud computing has been widely adopted as a paradigm for large-scale infrastructures.
In such a scenario, new security risks arise when different entities or domains share the same group
of resources. Involved organizations need to establish some kind of trust relationships, able to define appropriate
rules that can control which and how resources and services are going to be shared. The management
of trust relationships represents a key challenge in order to meet high security requirements in cloud computing
environments. This allows also to boost consumers confidence in cloud services, promoting its adoption.
Establishing trust with cloud service providers supports to have confidence, control, reliability, and to avoid
commercial issues like lock in. This paper proposes a survey of existing trust management models addressing
collaboration agreements in cloud computing scenarios. Main limitations of current approaches are outlined
and possible improvements are traced, as well as a future research path
