What Is a ‘Deep Reorg’ and Why Is It More concerning for Network Security?
A deep reorg is a chain reorganization that affects blocks that were mined many blocks ago (e.g. 100+ blocks).
It is highly concerning because it reverses transactions that the network and users had long considered final, fundamentally breaking the economic trust in the blockchain's immutability. A successful deep reorg is a clear indication of a successful, sustained 51% attack or a major protocol vulnerability.
Glossar
Reorg
Restructuring ⎊ This event signifies a fundamental alteration to the established order of the blockchain's history, typically resulting from a consensus failure or the discovery of a significant vulnerability.
Hash Rate Volatility
Fluctuation ⎊ The degree of short-term variability observed in the total computational effort securing a blockchain network.
Deep Reorg
Depth ⎊ A deep reorg is a chain reorganization event that affects a significant number of previously confirmed blocks, extending far back into the blockchain's history.