The advent of blockchain technology has caused a particular excitement across businesses and governments. Many researchers remain sceptical about the advantages of blockchain for DoD operations, and some point out that the structure of the technology may impede them. The so-called “immutability” of data in a blockchain is guaranteed as long as the network is big enough and the participation is well distributed among the users. But as we shall see, this isn’t always the case, and the defence sector should be aware of it. If a user is infected in a permissionless network (a network which you can join without having to ask for permission), and other users are aware of it, they can easily ignore him and the blocks he is attempting to post. But if data from a permissioned network owner or consortium member is accessed, it will have more severe implications. If the owner or part of the consortium is compromised, so is the network. Blockchain isn’t as invulnerable as is often thought, and we shall delve into its challenges and limits regarding its implementation in the defence sector. In this paper, we will examine how blockchain works and discuss its civilian and military uses. We shall see how numerous departments of defence all over the world are working on implementing blockchain technology for defence and security purposes. 
 This paper shall also address in detail the developments within the main countries and powers that are currently integrating blockchain into their armies, such as China, Russia and the United States. Beyond that, we shall analyse how blockchain, like any other new technology, still has its shortcomings. This leads us to the questions of whether blockchain has the potential to be a real game-changer in military affairs if it has been investigated thoroughly enough, and whether sufficient funds have been allocated to its optimisation.