Monero Under Siege: Qubic’s 51% Attack Sparks Chain Rewrite

• Qubic’s mining pool launches 51% attack on Monero blockchain, rewriting recent blocks.
• Sustaining the attack could cost up to $75M daily to maintain network hashrate control.
• Experts warn that the takeover allows double-spending and censorship of transactions.

Monero, one of the most prominent privacy-focused cryptocurrencies, is facing its most severe security challenge to date. Experts say the Qubic mining pool has successfully launched a 51% attack on the network. The move gives Qubic the power to rewrite blockchain history and disrupt the network’s core functions.

On August 12, SlowMist founder Yu Xian, also known as Cosine, confirmed the alarming development. He said Qubic now controls most of Monero’s hashrate. That control allows the pool to execute double-spend attacks and block specific transactions. “I’ve been following for a while, and this time the 51% attack on Monero seems to have succeeded,” Yu said.

Chain Reorganization Detected

The first signs of trouble came when analysts noticed a major chain reorganization early Tuesday morning. A reorganization occurs when a dominant mining entity replaces previously confirmed blocks with its own version of history. This action can reverse transactions that were considered final.

Charles Guillemet, CTO at Ledger, said the chain reorg strongly indicated a successful takeover. He explained that Qubic has been building its hashrate for months. That gradual accumulation eventually gave it majority control of the network’s computing power. “Monero appears to be in the midst of a successful 51% attack,” Guillemet wrote.

With the majority of the hashrate, Qubic can orphan any blocks mined by competing miners. This would make those blocks invalid, discouraging miners from continuing their work. Guillemet noted that a smaller $300 million market-cap chain is effectively overtaking Monero’s $6 billion network. He described the situation as unprecedented for a major privacy coin.

High Costs, Higher Risks

While the technical capability is clear, the economics remain uncertain. Yu Xian said the cost of sustaining the attack is extremely high. Guillemet estimated the daily expense could reach $75 million. These costs include the resources needed to maintain control over the network’s majority of the hashrate.

Despite the massive cost, potential short-term benefits would be huge. This would enable Qubic to roll back expensive transactions or double-spend on a large scale with control of the blockchain. This may enable the attackers to make profits before the market responds.

However, in the long run, the effects may be disastrous to all participants. A sustained 51% attack undermines trust in the network’s security. Businesses and investors who invest in Monero to make confidential transactions may lose confidence in the stability of the coin.

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Industry experts say that relevant platforms should remain alert. Exchanges, wallet providers, and payment services may need to increase security measures. The ability to rewrite the blockchain also enables censorship of any transaction. This could threaten the principles that privacy coins like Monero were built upon.

Wider Implications for Blockchain Security

The Monero incident has raised questions about blockchain security across the crypto industry. While 51% attacks are not new, they have never been common to large, established coins. Monero has long been seen as a stronghold of privacy and resistance to surveillance.

The attack raises concerns about the vulnerabilities that emerge in case mining power becomes concentrated in a single entity. Miners and developers might have to consider counter-offensive measures against the dominance of Qubic. Some of the possible responses are the alteration of the mining algorithm or other technical adjustments. For now, the network remains under Qubic’s control, and the risk of transaction reversals continues.