the current block-based data structure brings a number of issues, such as
- poor performance
- scalability,
- slow final confirmation
- centralization of powerful miners.
To resolve these issues, the Directed Acyclic Graph (DAG, see Figure 1) data structure has been emerged and it has been increasingly adopted in the field of Distributed Ledger Technology (DLT) [6].
DAG is a graph data structure that has emerged as a new form of DLT after the popular blockchain technology
