The Codex — Technical Grimoire

What is a BlockDAG?

A Block Directed Acyclic Graph (BlockDAG) is a generalization of the blockchain where each block can reference multiple predecessors. Instead of a single chain, the structure forms a DAG — a graph with directed edges and no cycles.

This allows:

• Multiple blocks created per second — miners don’t compete to orphan each other
• Higher throughput — the network’s full capacity is utilized
• Faster confirmations — no waiting for the next single block

The PHANTOM Protocol

PHANTOM solves the ordering problem in BlockDAGs. Given a DAG of blocks, PHANTOM:

1. Identifies a k-cluster — the largest set of blocks where each block is connected to all but at most k others
2. Uses this cluster as the “honest” set
3. Orders blocks by giving priority to cluster members

The parameter k relates to the network’s block creation rate and propagation delay, capturing how many parallel blocks honest nodes might create before seeing each other’s work.

The DAGKnight Protocol

DAGKnight advances PHANTOM by removing the need to set k in advance:

• It observes the DAG structure to infer network conditions in real-time
• Confirmation times adapt automatically — faster when the network is healthy, more cautious under attack
• It provides provable security without assumptions about propagation delay

The Kaspa Implementation

Kaspa is the first production implementation of a BlockDAG with PHANTOM/DAGKnight consensus:

• 1 block per second (targeting higher with future upgrades)
• GHOSTDAG variant for fast ordering
• Pruning to manage DAG growth over time
• Rust implementation (rusty-kaspa) for performance

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Explore the full technical documentation at vProgs.xyz or BlockDAG.xyz.