The aim of this thesis is to advance the knowledge on the efficient design and evaluation of distributed marketplaces with an emphasis on trust and privacy. Distributed systems are an integral part of today's computing infrastructures, enabling multiple nodes to work towards a common goal. Although distributed, most of today's computational systems are still built with a centralized architecture, which assumes complete governance by a single organization. In the case of centralized marketplaces, the correct trade execution guarantees, \ie digital trust, and data privacy are provided centrally, containing all processes and operations within a single organization's boundaries. This puts the marketplace operator in a prime position to govern trade settlement conditions. However, trust issues are raised if more than one organization has to govern the marketplace. In such a case, trust and privacy are decentralized, and control is distributed among all organizations which are part of the marketplace system. Thus, a decentralized marketplace requires a robust and secure consensus mechanism, which enables digital trust while allowing organizations to process and store private data for further usage in trade settlements. 

This thesis investigates both centralized and decentralized marketplace architectures applied to use cases of AI artifacts and renewable energy trading. It begins with a study of a marketplace for Artificial Intelligence (AI) artifacts where multiple organizations collaborate on AI pipeline execution. The study defines a Secure Virtual Premise, which enables AI pipeline execution in a centralized marketplace governed by a trusted third party. The thesis continues with a survey of the telecommunication services marketplaces, where both centralized and decentralized architectures are discussed. In addition, the survey provides an in-depth investigation of blockchain technology as a main trust-enabling platform, providing distributed storage and data assurance to all processes in a decentralized marketplace. Having mapped the state-of-the-art, the research shifts towards an in-depth investigation of blockchain-based decentralized renewable energy marketplaces. The main aim of such a marketplace is to incentivize the widespread adoption of renewable energy sources, resulting in the decarbonization of electricity distribution systems. The designed marketplace enables automation and trusted execution of peer-to-peer (P2P) energy trade settlements in decentralized systems while preserving users' data privacy. Furthermore, the marketplace is aligned with the data and P2P energy trade regulations. The studies provide an in-depth requirements definition, system architecture, implementation, and performance evaluation of marketplaces based on two major blockchain platforms. The final study of this thesis provides the improvements towards the renewable energy marketplace model aiming at an enhancement of trust, privacy, and scalability.