Reorganization
A chain reorganization where a competing branch replaces the current canonical chain.
A chain reorganization where a competing branch replaces the current canonical chain.
entity.trust_high
Sep 2026 · Freshness Score: 50%
Was ist Reorganization?
A chain reorganization where a competing branch replaces the current canonical chain.
- Category
- concept
- Type
- Authority Node
- Quellen
- 1
In PoW, if two miners find blocks at similar times, nodes may temporarily follow one chain; when the other grows longer, nodes switch, "reorganizing" out the shorter chain's blocks. Transactions in orphaned blocks return to the mempool. Dee
Reorgs are why zero-confirmation transactions are risky — a shallow reorg can undo a payment. Understanding reorg depth helps set confirmation thresholds. Attack-related reorgs threaten merchant and exchange security, especially on smaller
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Verwandt
1. What Is a Reorg
A reorg (chain reorganization) is a restructuring of a blockchain's recent blocks when a competing chain replaces the current one — typically from a mining race, fork, or attack. It can reverse transactions in the replaced blocks.
2. How It Works
In PoW, if two miners find blocks at similar times, nodes may temporarily follow one chain; when the other grows longer, nodes switch, "reorganizing" out the shorter chain's blocks. Transactions in orphaned blocks return to the mempool. Deep reorgs (attacker controlling hashpower) can enable double-spends. PoS finality prevents reorgs after finalization.
3. Why It Matters
Reorgs are why zero-confirmation transactions are risky — a shallow reorg can undo a payment. Understanding reorg depth helps set confirmation thresholds. Attack-related reorgs threaten merchant and exchange security, especially on smaller chains.
4. Key Facts
- Shallow reorgs (1-2 blocks) happen naturally on PoW chains
- 51% attacks can force deep reorgs
- PoS finality (e.g., Casper) makes finalized blocks irreversible
- Exchanges wait for confirmations to mitigate reorg risk
5. Related Concepts
- block-confirmation
- double-spend
- consensus
- full-node
Frequently Asked Questions
What is Reorganization?
A chain reorganization where a competing branch replaces the current canonical chain.
How does Reorganization work?
A reorg (chain reorganization) is a restructuring of a blockchain's recent blocks when a competing chain replaces the current one — typically from a mining race, fork, or attack. It can reverse transactions in the replaced blocks. In PoW, if two miners find blocks at similar times, nodes may tempor
Why does Reorganization matter in Web3?
- double-spend - consensus - full-node