  Conventional blockchains use consensus algorithms that totally order updates
across all accounts, which is stronger than necessary to implement a replicated
ledger. This makes updates slower and more expensive than necessary. More
recent consensus-free replicated ledgers forego consensus algorithms, with
significant increase in performance and decrease in infrastructure costs.
However, current designs are based around reliable broadcast of update
operations to all replicas which require reliable message delivery and
reasoning over operation histories to establish convergence and safety.
  In this paper, we present a replicated ledger as a state-based conflict-free
replicated data type (CRDT) based on grow-only counters. This design provides
two major benefits: 1) it requires a weaker eventual transitive delivery of the
latest state rather than reliable broadcast of all update operations to all
replicas; 2) eventual convergence and safety properties can be proven easily
without having to reason over operation histories: convergence comes from the
composition of grow-only counters, themselves CRDTs, and safety properties can
be expressed over the state of counters, locally and globally. In addition,
applications that tolerate temporary negative balances require no additional
mechanisms and applications that require strictly non-negative balances can be
supported by enforcing sequential updates to the same account across replicas.
  Our design is sufficient when executing on replicas that might crash and
recover, as common in deployments in which all replicas are managed by trusted
entities. It may also provide a good foundation to explore new mechanisms for
tolerating adversarial replicas.
