“…Specifically, PoS protocols, which select participants to compose blocks based on their possession of some scarce resources, demand additional security assumptions and protection mechanisms to prevent attackers from generating conflicting histories. These assumptions, however, are often difficult to meet [4], [65], and new attack vectors emerge even when the protection mechanisms are in place [11], [30], [42], [58]. BlockDAG protocols, which replace NC's linear blockchain structure with a direct acyclic graph of blocks, either abandon the global order of transactions [78], therefore limiting the smart contract functionality, or do not specify their transaction fee distribution [2], [50], [79] or DAM [2], [5], [79], rendering a complete security analysis infeasible.…”