  A significant portion of research on distributed ledgers has focused on
circumventing the limitations of leader-based blockchains mainly in terms of
scalability, decentralization and power consumption. Leaderless architectures
based on directed acyclic graphs (DAGs) avoid many of these limitations
altogether, but their increased flexibility and performance comes at the cost
of increased design complexity, so their potential has remained largely
unexplored. Management of write access to these ledgers presents a major
challenge because ledger updates may be made in parallel, hence transactions
cannot simply be serialised and prioritised according to token fees paid to
validators. In this work, we propose an access control scheme for leaderless
DAG-based ledgers which is based on consuming credits rather than paying fees
in the base token. We outline a general model for this new approach and provide
some simulation results showing promising performance boosts.
