In recent years there has been a significant growth of interest and investment in Blockchain technology with a many companies and government organisations, large and small, proposing applications of this technology across a range of social, financial, industrial, and governmental sectors. Blockchain technology is seen as providing opportunities to disrupt traditional products and services. This is mainly due to features such as the absence of a single trusted third party, the immutability of the blockchain record, the distributed, decentralised nature of blockchains, and the ability to run smart contracts. The International Data Spaces (IDS) reference architecture focuses on the concept of ‘data sovereignty’, allowing organizations to share datasets in a secure and controlled way using the International Data Spaces Connector concept. Some of the features of blockchain technology are consistent with features of the International Data Spaces architecture, such as the absence of a single trusted party (e.g. where all data is being stored) and the decentralized nature. Other features are complementary, such as the permanence of the blockchain record. This makes it highly interesting to explore how IDS and blockchain technology fit together and how blockchain technology could be used in future versions of the International Data Spaces reference architecture. IN THIS DOCUMENT WE WILL HIGHLIGHT: • The core concepts of blockchain technology • Potential usage scenarios for blockchain technology in an IDS context • Possibilities for implementing IDS architectural concepts using blockchain technology • How several projects currently use IDS in combination with blockchain technology