Blockchain Agnostic Protocols: An Analysis of the State of the Art

Blockchain is a relatively new technology that has attracted great interest in academia and industry. Given the characteristics of blockchains, the problem of inter-chain communication has become a hot topic. Numerous approaches to the problem have been proposed in order to transfer cryptocurrencies or tokens between different blockchains. However, to make the blockchain widely used, inter-chain communication must be extended to generic messages. In this article we consider some approaches to the problem that aim at generalising the possibilities of communication. These approaches are called agnostic protocols. Our main contribution consists in presenting some emerging standards for the development of agnostic blockchain protocols, illustrating some projects that use them and understanding their peculiarities. We analyse how these protocols work, how agnostic they are and how much they lend themselves to generalising the problem of cross-chain communication between blockchains.