Qubic’s 51% Attack Threatens Monero’s Privacy and Decentralization

Monero, a cornerstone of privacy-focused cryptocurrencies, faces a novel and alarming challenge as Qubic, a mining pool spearheaded by Sergey Ivancheglo, launches what many in the crypto community describe as an economic attack. Unlike traditional attacks that exploit software vulnerabilities, this campaign leverages financial incentives to lure miners away from Monero’s network, aiming to secure a majority of its hashrate.

With Qubic’s share of Monero’s computing power climbing from a mere 2% in May 2025 to over 10% recently, the threat of a 51% attack is starting to loom, potentially undermining Monero’s core principles of decentralization and privacy. This development signals a new frontier in crypto warfare, where economic strategies could reshape the landscape of proof-of-work networks.

A New Kind of Crypto Warfare

Qubic’s approach hinges on a compelling economic model that entices miners with higher rewards paid in its native $QUBIC token, rather than Monero’s $XMR. By selling mined $XMR to purchase and burn $QUBIC tokens, Qubic creates a deflationary cycle that boosts its token’s value, drawing more miners to its pool. This strategy has proven effective, with Qubic’s hashrate surging and positioning it as a dominant force in Monero’s mining ecosystem. Posts on X and discussions on platforms like Reddit highlight Qubic’s rapid ascent, noting its claim to nearly 38% of Monero’s total hashrate at its peak, a figure that raises red flags for the community.

The cost of this attack is strikingly low compared to Monero’s daily security budget of approximately $130,000. Estimates suggest Qubic could secure majority control by offering a 10% premium, costing just $7,000 to $10,000 daily. This affordability stems from Monero’s RandomX algorithm, which prioritizes CPU mining to resist specialized hardware but leaves the network vulnerable to economic manipulation due to its modest block reward of 0.6 XMR and low transaction fees. With only around 30,000 transactions processed daily, Monero’s economic defenses struggle to compete with Qubic’s incentivized model.

Sergey Ivancheglo, also known as Come-from-Beyond from his IOTA days, has framed this initiative as a demonstration of Qubic’s Useful Proof of Work (uPoW) system, which integrates Monero mining with other computational tasks like AI training. While Ivancheglo insists there is no intent to harm Monero, his social media posts advising exchanges to require 13 confirmations from August 2 to August 31, 2025, suggest a calculated move that could disrupt transaction reliability. Such actions could enable Qubic to orphan competing miners’ blocks, delay confirmations, or even push protocol changes, threatening Monero’s decentralized ethos.

The Monero community has responded with urgency, activating safety measures and promoting decentralized mining solutions like P2Pool to counter Qubic’s growing influence. Discussions on Reddit emphasize the need for exchanges to enforce higher confirmation requirements and for miners to avoid centralized pools. Some community members advocate for a hard fork to adjust the RandomX algorithm, though such changes must carefully preserve Monero’s commitment to privacy and accessibility. Despite these efforts, awareness remains limited, with many users potentially underestimating the severity of this economic threat.

This attack underscores a broader shift in cryptocurrency conflicts, moving from technical exploits to economic and social engineering. Qubic’s ability to dominate Monero’s hashrate without relying on cryptographic flaws highlights the fragility of proof-of-work networks when faced with well-funded, incentive-driven campaigns. The community’s response in the coming weeks will be critical, as Monero’s survival as a privacy sanctuary depends on its ability to bolster honest mining incentives and distribute hashpower more evenly.