Kaspa processes multiple blocks per second, far faster than traditional blockchains. In a high-speed DAG (Directed Acyclic Graph), blocks arrive out of order, in parallel, and sometimes simultaneously from different regions of the world. Maintaining a single, consistent, deterministic ordering across all nodes is therefore one of Kaspa’s most important challenges.
Kaspa solves this with a combination of GHOSTDAG, blue set selection, blue score, and a robust DAG-aware ordering algorithm.
Here’s how Kaspa ensures that every node ends up with the same block ordering — even at extremely high throughput.
1. GHOSTDAG: The Core of Deterministic Ordering
Kaspa’s ordering comes from the GHOSTDAG consensus algorithm.
Unlike longest-chain protocols, GHOSTDAG allows nodes to:
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accept all valid blocks
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incorporate them into the DAG
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compute a deterministic order afterward
GHOSTDAG evaluates the DAG’s structure and selects the most “well-connected” blocks — known as the blue set — to form the backbone of ordering.
This makes ordering consistent even when multiple blocks arrive at the same time.
2. Blue Set vs. Red Set Classification
Kaspa classifies each block into one of two categories:
Blue Blocks
Blocks that align well with the major flow of the DAG and are well-connected.
Red Blocks
Blocks that diverge slightly from the core DAG structure or arrive later.
Ordering is then derived by:
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Selecting the blue set
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Sorting blue blocks by score
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Inserting red blocks deterministically
This classification ensures all nodes agree on:
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which blocks are “blue”
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which blocks are “red”
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how to position them consistently
3. Blue Score: A Deterministic Ranking System
Each block receives a blue score, which counts how many blue blocks exist in its past.
Ordering priority is simple:
More blue score = higher priority in ordering
Because blue score is computed deterministically from the DAG structure — and all nodes see the same structure — every node reaches the same ordering naturally.
4. Ordering Happens After Blocks Are Accepted
Traditional blockchains must decide ordering as blocks arrive, leading to:
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reorgs
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chain splits
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inconsistencies
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orphan races
Kaspa flips the model:
✔ Nodes accept all blocks immediately
✔ Ordering is computed deterministically afterward
This means even if blocks arrive out of order, the final ordering is always the same.
5. DAG Traversal Algorithms Ensure Consistency
To compute the order, nodes traverse the DAG using:
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depth-first search
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parent-first prioritization
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deterministic conflict resolution rules
Every node follows the same exact algorithm, so the ordering result is always identical.
Even if the arrival sequence of blocks differs per node, the ordered DAG sequence remains stable across the network.
6. Parallel Block Processing Removes Timing Bias
In traditional chains, the earliest-arriving block wins.
Kaspa avoids timing bias entirely:
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all blocks are included
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block ordering depends on connectivity, not arrival time
This eliminates fairness issues from:
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geographic latency
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network slowdowns
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miner advantage
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propagation delays
Timing does not affect ordering — structure does.
7. Topological Sorting Ensures Valid Final Order
Once blue and red sets are classified, Kaspa performs a topological sort, ensuring:
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parent blocks always appear before children
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all nodes produce the same linear sequence
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ordering is compatible with DAG dependencies
The result is a single, canonical ordering identical across all nodes.
8. GHOSTDAG Provides Reorg-Free Ordering
Because Kaspa accepts all valid blocks and orders them deterministically:
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reorgs are extremely rare
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deep reorgs are virtually impossible
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ordering is stable from the moment a block is seen
Reorg storms — a major problem for high-speed blockchains — are eliminated by design.
Conclusion
Kaspa maintains consistent ordering in high-speed DAGs through a combination of:
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GHOSTDAG consensus
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blue set / red set block classification
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blue score ranking
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DAG-aware ordering rules
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topological sorting
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parallel block acceptance
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ordering based on structure, not timing
This architecture allows Kaspa to process multiple blocks per second while still guaranteeing that every node converges on the same exact transaction and block order — reliably, deterministically, and without reorg instability.