Directed Acyclic Graph Based Blockchain Systems

Blockchain technology has been revolutionizing many fields since last decade. Its true potential is not practically utilized yet. In a very short period of time, it has evolved twice - Smart contracts and Directed Acyclic Graph (DAG). DAG based blockchains currently referred to as Blockchain 3.0 solves many issues in the current conventional blockchain technologies including transaction fees, transaction approval times and scalability. In this paper, we present a comparative analysis of blockchain implementations based on DAG including IOTA, NxT, Byteball, Nano, DAGCoin, Fantom, XDAG and Caixapay. We discuss limitations of both conventional and DAG based blockchains and suggest when to prefer DAG based blockchains.