Monero's Recent Reorganization: What Happened?

Monero (XMR) recently experienced a substantial blockchain reorganization, the largest in its 12-year history. This event resulted in the rollback of 18 blocks, effectively erasing approximately 36 minutes of transaction data and invalidating 118 transfers.

What Caused the Reorg?

The reorg occurred between September 14th and 15th at block height 3,499,659. The mining pool Qubic is suspected of releasing a privately mined, longer chain that then overtook the main network.

This type of activity is often referred to as "selfish mining," where miners withhold blocks they discover and then release a longer chain to rewrite recent transaction history.

Impact on Monero

While the XMR token experienced a short term price increase, the reorganization raises serious concerns about the security and immutability of the Monero blockchain. The event highlighted the vulnerability to potential 51% attacks, where a single entity controls a majority of the network's computing power.

The previous rule of thumb of 10 confirmations being sufficient for transaction finality has also been called into question. Exchanges may need to increase their confirmation requirements as a result.

Some community members have expressed concerns about the concentration of mining power and have suggested moving to smaller pools to increase decentralization.

Key Takeaways:

• Monero experienced a significant blockchain reorg, erasing 36 minutes of transaction data.
• The incident was potentially caused by "selfish mining" activity.
• The reorg raises concerns about Monero's security and the adequacy of existing confirmation times.