BlockDAG
15/04/2026
A BlockDAG (Block Directed Acyclic Graph) is an evolution of the traditional blockchain architecture. Instead of a single linear chain where only one block can be added at a time, a BlockDAG allows multiple blocks to be created simultaneously — all of them valid and included in the ledger.
The problem BlockDAG solves
In a traditional blockchain with fast block times, two miners can find valid blocks at the same moment. Since only one can be accepted, the other becomes an orphan block — the miner's work is wasted and the transactions are not confirmed. This forces networks like Bitcoin to use slow 10-minute block times to minimize orphans.
BlockDAG eliminates this tradeoff: all simultaneously mined blocks are included in the DAG, so no work is wasted.
How BlockDAG works
Instead of each block pointing to exactly one parent, blocks in a DAG can reference multiple parents. A consensus algorithm (like PHANTOM or GhostDAG) then determines the canonical ordering of transactions across all blocks.
BlockDAG networks
- Kaspa (KAS) — the most prominent BlockDAG network, using the GhostDAG/DAGKNIGHT protocol. Achieves 1–10+ blocks per second with full PoW security.
- Alephium (ALPH) — uses a sharded BlockDAG with 16 parallel chains, achieving high throughput while supporting smart contracts.
BlockDAG vs Blockchain
| Blockchain | BlockDAG | |
|---|---|---|
| Structure | Linear chain | Directed graph |
| Parallel blocks | Not allowed (one wins, others orphaned) | All included |
| Block time | Slow (to avoid orphans) | Can be very fast |
| Throughput | Limited | High |
| Examples | Bitcoin, Monero | Kaspa, Alephium |
