DAGbased

DAGbased refers to distributed ledger or data-structure designs that use a directed acyclic graph (DAG) as the core representation of transactions or events. In a DAG-based system, each new unit (often a transaction or event) references one or more earlier units, creating edges that form a graph with no cycles. This structure contrasts with a single linear blockchain and enables greater concurrency and parallel processing of validations.

Consensus and ordering in DAG-based ledgers are typically achieved without a single linear chain. Instead, participants validate past units and build consensus through mechanisms such as tip selection (choosing unconfirmed units to approve) and cumulative weight, sometimes aided by voting or probabilistic finality. Finality is often probabilistic and improves as more units confirm earlier ones.

Advantages include potential higher throughput and lower latency, better scalability under high load, and the possibility of low or no transaction fees, since validation work is distributed across many participants and can occur in parallel. These properties make DAG-based designs attractive for microtransactions and Internet of Things use cases.

Security and design challenges include ensuring robust finality guarantees, defending against parasite chain or double-spending attempts before a unit has enough confirmations, and choosing safe tip-selection and validation rules to avoid centralization or preferential treatment. Real-world deployments must address network delays, storage growth, and incentive alignment to maintain network health and reliability.

Notable examples and research include IOTA's Tangle, Byteball, and other DAG-based ledgers, as well as academic and industry exploration into consensus protocols suitable for DAG structures. The field remains active, with ongoing work on formal safety proofs, interoperability, and governance models.