Did Qubic Actually 51%-Attack Monero, or Just Win the Headlines?

A project built around a $300 million AI token spent August claiming it had overpowered a privacy-focused blockchain worth roughly $6 billion — and the details of that claim turned out to be far messier than the victory announcement suggested.

Over several months, Qubic ran a deliberate campaign: pay Monero miners roughly triple the going rate to redirect their hashpower toward Qubic's pools, build up a dominant share of Monero's network, then stage what it described as a textbook 51% attack, complete with reorganized blocks and warnings to exchanges.

On August 12, Qubic published a blog post declaring the mission accomplished, framing the episode as "history in the making" and asserting it had taken over Monero's consensus process. Supporting evidence cited included six reorganized blocks and sixty orphaned blocks within a 24-hour span.

Independent data told a less dramatic story. Pool statistics put Qubic's share closer to 30% of Monero's hashrate rather than a true majority, and notably, Qubic's own public dashboards went dark right as the attack was supposedly unfolding.

Whether this was genuine stress-testing of Monero's security model or a choreographed event meant to drive up the QUBIC token remains an open question — one where the attacker and the marketer appear to be the same party.

01How the campaign was built

Qubic's move into Monero mining was not opportunistic — it was engineered from the start. The project markets itself around "Useful Proof of Work," an approach where mining hardware also contributes computation to Qubic's onchain AI system, AIGarth, rather than burning cycles on hashes with no other purpose, as in Bitcoin. Officially, the Monero campaign was framed as a proof of concept: evidence that the same mining infrastructure could switch between AI training and cryptocurrency mining on demand.

To pull miners in, Qubic offered a return roughly three times what Monero mining alone would pay. The mechanism behind that premium was straightforward: Qubic mined XMR through its pools, sold it, used half the proceeds to buy back and burn QUBIC tokens, and paid the remaining half out to miners as extra rewards — effectively turning Monero mining into fuel for QUBIC's deflationary supply mechanics.

The shift in hashrate happened gradually. Epoch by epoch, Qubic's share of Monero's network climbed from under 2% to more than 27%, and the project says its peak hashrate reached 2.77 GH/s — close to half of Monero's total computational power by its own accounting.

At that point, Qubic put the next step to a community vote: should its validators start orphaning blocks mined by everyone else on Monero once the 51% threshold was crossed? The vote passed — though whether that represents governance in action or simply retroactive cover for a plan already in motion is a matter of interpretation.

02The announcement

The warning came a day ahead of the claimed event. On August 11, Qubic founder Come-from-Beyond posted a mild advisory to Monero holders that some disruption was coming.

Come-from-Beyond is better known as Sergey Ivancheglo, who co-founded IOTA before leaving amid public disputes and who also created NXT, one of the earliest proof-of-stake blockchains. His former IOTA co-founder once described his "unorthodox actions as it pertains to communication" — a polite way of saying he's technically gifted and prone to controversy.

In line with that reputation, his warning was couched in careful technical language: between specific UTC time windows, Qubic and Monero-adjacent teams would run a "controlled test" that could raise the orphan-block count. Nothing to be alarmed about, he said — just don't fall for the FUD.

A day later, Qubic declared success. Its blog post stated: "History was made as the Qubic protocol successfully completed its attempt to dominate the Monero network," claiming 51% hashrate dominance and a successful chain reorganization. The cited evidence: six blocks reorganized and sixty orphaned in a single day. A Qubic contributor known as dkat said they had mined 63 out of a 122-block window — above the 51% target.

The technique used was selfish mining: mine blocks privately, withhold them, then release a longer chain that invalidates everyone else's work — a well-known game-theoretic strategy in proof-of-work systems. Come-from-Beyond played the role of the gracious victor, having flagged the coming orphan blocks in advance and asserting technical dominance once it was over. A commentator on X, CaffeinatedUser, summarized the implication: "They intend to orphan all blocks from every other miner, making themselves the only mining entity of Monero." A far smaller project had, on paper, humbled a much larger one.

Yet Qubic itself added a caveat to its own victory: it chose not to push for full control of Monero's consensus, citing "internal discussions on whether that would hurt Monero's price." Framed as restraint, the statement also raises the question of whether the exercise was really about testing network security or about managing its own public image.

03Pushback from the community

Not everyone accepted the takeover narrative. Luke Parker, lead developer at SeraiDEX, challenged the claim directly: "A 6 re-org does not mean a '51% attack' was successful." He noted that genuine 51% attacks produce reorganizations of unbounded depth and full censorship of competing pools — this event showed neither, and he characterized it instead as a lucky run combined with elevated hashrate.

Reddit users began comparing Qubic's self-reported figures against independent pool trackers, and the numbers didn't match. Qubic had claimed a peak of 3.01 GH/s, while outside tracking put Monero's total network hashrate at around 5 GH/s; by that same data, Qubic's current rate was only 2.08 GH/s — closer to 40% of the network than the 51% needed for the claimed attack.

Adding to the suspicion: Qubic had disabled its public API stats shortly before announcing the "takeover" — an inconvenient gap for a project claiming transparency. Monero's community responded with organized boycotts and campaigns to redirect hashrate away from Qubic's pools, which reportedly cut Qubic's share from around 45% down to under 15% within hours.

Community sentiment ran skeptical. One Reddit comment put it this way: "They infiltrated the monero discord about a month ago and started spamming us with their nonsense. We theorize it could be some kind of psy op... there's simply too many fake supporters." On X, a user going by tuxsudo made a similar point: "They disabled API hashrate reporting so that they could lie about it." Several analysts concluded the episode amounted to marketing dressed up as a network attack, with mining as a secondary detail. As the scrutiny mounted, the picture that emerged was one of streaky luck and inconsistent numbers, not a demonstrated takeover — with the timing lining up suspiciously well with Qubic's own token-burn announcements.

04The token-burn angle

Qubic's Monero campaign functioned as much as a token-burning mechanism as a security demonstration. The design was simple: mine XMR, convert it to cash, use that cash to buy QUBIC on the open market, and burn the tokens to shrink supply and support the price.

At its peak, Qubic reported burning 33.5 billion QUBIC tokens at an average rate of $2,280 per billion tokens; the epoch before that, it had burned 65.9 billion QUBIC, all funded through the Monero mining operation. Notably, the reported mining result of 63 blocks out of a 122-block window works out to precisely 51.6% — just enough to clear the "51% attack" bar the project wanted to claim. Qubic's periodic updates consistently emphasized burn totals ahead of mining details, and the community vote that authorized "orphaning other miners" can equally be read as a vote about token economics as about network security.

05Conflicting hashrate figures

The underlying numbers proved hard to pin down. Qubic maintained it hit a 2.77 GH/s peak hashrate and that dkat's 63-of-122 block count equaled 51.6% of the network. Outside sources disagreed: Monero's total network hashrate during the event was measured at 4.99 GH/s, while MiningPoolStats showed Qubic with no reported hashrate after it stopped publishing data on July 30 — Qubic having pulled its stats from public view right before the claimed takeover.

SlowMist's founder, posting as Cos, said the attack "seems to have succeeded", and secondary reporting cited a Qubic hashrate share of 52.36% — though that figure traced back to Qubic's own systems, the same ones that had just stopped publishing externally. A Hacker News analysis found that the "Unknown" mining-pool category on Monero jumped from roughly 3% to roughly 23% during the period, implying Qubic's real control was closer to 20%.

Market reaction was muted relative to the scale of the claim: XMR fell about 10%, a notable move but nothing near the damage seen in confirmed 51% attacks — Bitcoin Gold, for comparison, lost more than half its value during its own majority-hashrate attacks. Within hours, community-driven boycotts pushed Qubic's hashrate share below 14%. The measurable damage — six blocks reorganized, sixty orphaned — was enough to generate headlines but well short of the unbounded disruption a genuine 51% attack would cause.

06What it says about proof-of-work economics

Strip away the framing, and the core mechanism was economic, not technical: Qubic didn't need a novel exploit, it simply outbid Monero miners. Tripling mining rewards proved more persuasive than any ideological attachment to decentralization, and miners reallocated their hardware accordingly.

The episode is less a story about Monero specifically than about a structural weakness shared by proof-of-work networks generally: any chain with moderate mining rewards is exposed to a well-capitalized actor willing to pay a premium for hashpower. It also demonstrated that majority control isn't strictly necessary to cause majority-level disruption — selfish mining executed with only 33-40% of hashrate, combined with well-timed messaging, produced market panic comparable to an actual 51% attack. In that sense, perception moved faster than the blockchain's own confirmations.

The distinction between legitimate security research and a profitable FUD campaign becomes hard to draw when the "research" also generates billions worth of token burns while depressing a competitor's price. The sequence — announce the experiment, accumulate hashrate, declare victory, highlight the token metrics, then decline to fully seize consensus "because of internal discussions on whether that would hurt Monero's price" — fits a pattern consistent with Come-from-Beyond's history. Described elsewhere as the figure behind both NXT and IOTA, he has a track record of pairing strong technical execution with maximum public controversy. When accused on X of being "sponsored by 3-letter agencies to attack this anon coin," he responded by reframing the campaign as a favor — preparing Monero's defenses against future state-level attacks.

Whether or not that framing holds up, the practical outcome may not depend on it. Qubic's narrative of AI-driven dominance became, for a short window, effectively real simply because enough people believed and repeated it.

Regardless of whether Qubic ever genuinely held 51% of Monero's hashrate, the project secured substantial token burns, a marketing win, and a "takeover" story that reads more convincingly in headlines than in the underlying blockchain data. The narrative spread, QUBIC's burn mechanics kept running, and XMR holders absorbed the price impact regardless of the technical fine print. Monero's network continued operating normally throughout, but the reputational and price damage had already landed before any rebuttal could catch up — a reminder that in this instance, a profitable mining operation was successfully rebranded as a historic attack, and a token-burn program was successfully rebranded as security research.