  Today, Internet of Things (IoT) devices are the powerhouse of data generation
with their ever-increasing numbers and widespread penetration. Similarly,
artificial intelligence (AI) and machine learning (ML) solutions are getting
integrated to all kinds of services, making products significantly more
"smarter". The centerpiece of these technologies is "data". IoT device vendors
should be able keep up with the increased throughput and come up with new
business models. On the other hand, AI/ML solutions will produce better results
if training data is diverse and plentiful.
  In this paper, we propose a blockchain-based, decentralized and trustless
data marketplace where IoT device vendors and AI/ML solution providers may
interact and collaborate. By facilitating a transparent data exchange platform,
access to consented data will be democratized and the variety of services
targeting end-users will increase. Proposed data marketplace is implemented as
a smart contract on Ethereum blockchain and Swarm is used as the distributed
storage platform.
