  We design TimeBoost: a practical transaction ordering policy for rollup
sequencers that takes into account both transaction timestamps and bids; it
works by creating a score from timestamps and bids, and orders transactions
based on this score.
  TimeBoost is transaction-data-independent (i.e., can work with encrypted
transactions) and supports low transaction finalization times similar to a
first-come first-serve (FCFS or pure-latency) ordering policy. At the same
time, it avoids the inefficient latency competition created by an FCFS policy.
It further satisfies useful economic properties of first-price auctions that
come with a pure-bidding policy. We show through rigorous economic analyses how
TimeBoost allows players to compete on arbitrage opportunities in a way that
results in better guarantees compared to both pure-latency and pure-bidding
approaches.
