Qubic, an AI protocol, has reportedly taken control of Monero following a 51% attack on the privacy blockchain. This attack could potentially allow Qubic’s mining pool to manipulate transaction data and other information. However, security experts have expressed doubts about the success of the event.
The group behind Qubic claimed that their “experiment” was successful and was conducted to help protect the network against future attacks.
“Qubic has attained over 51% of Monero’s hashrate, effectively granting it control over the network,” the company stated in a post referencing their blog entry. “While Qubic has not yet initiated the takeover, the question remains: what’s next for Qubic and the future of proof-of-work chains?”
A 51% attack occurs when a single entity or group of miners controls a majority of a proof-of-work blockchain network’s hash rate, potentially enabling them to manipulate transactions and double-spend coins. Notable proof-of-work chains like Bitcoin, Dogecoin, and Monero have all been targeted by such attacks.
Qubic has attained over 51% of Monero’s hashrate, effectively granting it control over the network.
Qubic has chosen not to execute the takeover yet, demonstrating a powerful concept through action.
However, the story is far from over. What lies ahead for Qubic and the future of PoW chains?
Article below⏬ pic.twitter.com/JqQNqpy95j
— Qubic (@_Qubic_) August 12, 2025
This attack has reignited concerns about a vulnerability in blockchain technology that can be exploited by attackers for personal gain, to the detriment of users. Ethereum Classic, Verge, and Bitcoin Gold have all previously fallen victim to similar attacks between 2018 and 2020.
Qubic is a proof-of-work blockchain that utilizes the computational power of the consensus mechanism to support its AI model. The QUBIC token has seen a 25% increase in value over the past 24 hours, reaching a market cap of $342 million according to CoinGecko. On the other hand, Monero’s XMR has experienced a 6% decline and currently holds a market cap of $4.75 billion.
Despite claims by Qubic, some experts such as AMLBot and Horizen Labs have raised doubts about the success of the attack. AMLBot pointed out the absence of significant blockchain rewrites as evidence of the attack’s success, while also warning that the attack may still be ongoing. Horizen Labs highlighted the lack of independent verification to confirm the attack.
James Shuman, head of security at Horizen Labs, mentioned that while Qubic reported briefly attaining majority hashrate and experiencing elevated orphaning/short reorganizations, there is no independent confirmation of a successful attack or double-spends at this time.
However, Retrodrive from Qubic assured that proof of the attack is readily available on-chain and easy to verify. In a window of 122 blocks, Qubic reportedly mined 63 blocks, surpassing their own performance target of 51%.
Other blockchain security experts have claimed that the data they have analyzed indicates the success of the attack. Nikita Zhavoronkov, CEO of Blockchair, stated that Monero had undergone deep reorganizations, which he defines as a successful 51% attack, albeit with low impact and short duration.
Qubic’s leader, Eugene Ivanchenko (also known as Come-from-Beyond), stated that the attack was conducted to help Monero prepare for potential future conflicts with government agencies. Retrodrive emphasized that Qubic’s intention was not to harm Monero.
Given Monero’s reputation as a privacy-focused blockchain favored by malicious actors, governments may seek to target it in the future. However, maintaining control of a decentralized protocol can be financially burdensome due to the high computational requirements of controlling the majority of the hash rate.
According to the AMLBot investigations team, the cost of maintaining control over the blockchain is exorbitant, estimated at $75 million per day by Ledger CTO Charles Guillemet. This level of control could erode confidence in the network and discourage other miners from participating, effectively centralizing mining activities under Qubic’s control.
In a blog post, Qubic stated that their ultimate goal is for Monero’s security to be upheld by their miners. Retrodrive mentioned that once Qubic fully secures the Monero chain, the profitability for Qubic’s miners will increase significantly, as non-Qubic miners will no longer receive rewards.
Shuman emphasized that this event raises concerns about the vulnerability of the system and the potential for well-funded actors to exploit off-chain incentives to centralize proof-of-work protocols. He urged for diversification of hash power and the establishment of decentralized defaults as standard practice.
Qubic celebrated their success in a blog post, claiming to have “rewritten the rules of blockchain competition” and asserting dominance over Monero, despite being a smaller AI protocol in terms of market cap. The implications of this event are expected to have a lasting impact on the crypto industry.
