Blockchain is a relative recent research and technological trend, with applications in diverse domains including those associated with a nation’s critical infrastructure sectors (e.g., chemical, commercial facilities, communications, critical manufacturing, dams, defense industrial base, emergency services, and energy). The interest in blockchain is also partly evidenced by the number of submissions we received in this special issue. Of the 54 submissions received, 18 papers were accepted after several rounds of reviews by subject matter experts (i.e., acceptance rate of $\sim$33.3%). This special issue presents the research advances and describes existing and emerging challenges outlined in these 18 accepted papers, authored by researchers from institutions in Australia, Canada, China, Denmark, Ireland, New Zealand, Spain, United Kingdom, and United States. These accepted papers also reinforce the importance of collaboration across institutions and countries.