Monero vs. Qubic Drama

[OmegaStarScream]

I have been seeing a lot of posts (contradicting ones too) lately about Monero, and how Qubic has now the ability to pull a 51% attack because they control most of the mining power. On the other hand, I have also seen posts on X saying that Qubic is lying, and that it's true....

I'd appreciate if someone could shed more light on this as this looks like an attack on the integrity of the network whether the attack is real or a lie.

[Dogedegen]

Having the ability to do a 51% attack is not the same as doing an attack. There are times where it seems from research that Qubic may have had sufficient hashrate to attack monero but one must keep in mind that the hashrate data is also at times questionable.

What is an attack? It would be for example Qubic selling Monero on an exchange for another crypto asset and then reverting the chain sufficiently back enough to steal back the Monero. I mean this sounds scary, but if you are a public person or legal entity you are basically committing a crime in public and this could turn out really bad for you really fast. Things are not as simple as they seem.

As of now there have been no reported cases of this happening. Discussions are underway for potential countermeasures.

[d5000]

I am sometimes following the statistics a bit.

There's the (self-claimed) pool data from Qubic here: https://qpools.qubicdisciple.info/

The other site I'm looking at is a general Monero pool statistic site: https://miningpoolstats.stream/monero



In the second one you which is the one I posted an image from, you can see that the Qubic hashrate currently is at approximately 28% of the known network hashrate. Judging from the small chart it looks however they were significantly over 40% on August 14 during some moments, maybe close but probably not over 50% (their best percentage was when they reached 3 GH/s and hashvault.pro had under-average hashrate, from a first glance it seems in these moments the other pools together had about 3.4 GH/s). They seem to have done some selfish mining and thus have orphaned some other blocks.

It is of course concerning that someone with deep pockets can accumulate so much hashrate, but the incentives of course are still in place, sustaining the attack is costly and provides no real profit.

Such big coins like ETC, BSV, Grin (when it was still big) and if I remember correct even BCH have also suffered 51% attacks in the past, and in these cases it looks they were succesful.

[Despairo]

In the second one you which is the one I posted an image from, you can see that the Qubic hashrate currently is at approximately 28% of the known network hashrate. Judging from the small chart it looks however they were significantly over 40% on August 14 during some moments, maybe close but probably not over 50% (their best percentage was when they reached 3 GH/s and hashvault.pro had under-average hashrate, from a first glance it seems in these moments the other pools together had about 3.4 GH/s). They seem to have done some selfish mining and thus have orphaned some other blocks.

Qubic's pool hashrate ATH was 3.3 GH/s, at that time Monero's total pool hashrate was 6.6 GH/s, so technically it's 50%.

They're planning to attack Doge https://coinfomania.com/qubic-dogecoin-attack/ and also threatening Zcash https://www.mitrade.com/insights/news/live-news/article-3-1046147-20250817

What is this all about? Qubic only targeting privacy coins instead of centralized coins like OFFICIAL TRUMP.

[d5000]

Qubic's pool hashrate ATH was 3.3 GH/s, at that time Monero's total pool hashrate was 6.6 GH/s, so technically it's 50%.

I'd be interested in a more exact breakdown, do you have a link to the total hashrate graph for Monero exact enough to see the proportion also for e.g. 10-minute intervals? I see the 3.33 ATH at the qubicdisciple site, but on the general Monero stats site the highest value was 3.02, which is probably because the 3.33 were only reached for a very short time.

For selfish mining, as the 6-block reorg showed, you don't need necessarily 51% for a long period but 33% are already enough.

I would only consider it a successful attack if they were sustaining the 51% for about an hour. In BTC, normally you would consider an attack successful if you can rewind 6 confirmations. But Monero has only a 2-minute block interval, so 6 XMR confirmations are basically nothing, little more than a single BTC conf which can be orphaned at any time and with a much smaller hashrate (and no exchange of my knowledge would accept XMR after only 6 confirmations).

But of course that problem is the reason why so many smaller PoW altcoins switched to a hybrid PoW/PoS model, already after the ETC/Grin attacks in the late 2010s.

They're planning to attack Doge https://coinfomania.com/qubic-dogecoin-attack/ and also threatening Zcash https://www.mitrade.com/insights/news/live-news/article-3-1046147-20250817

Zcash had already a similar situation in 2023, when ViaBTC acquired 51% of their hashrate, but afaik didn't attack it. (Well, even Bitcoin had a situation in 2014 or so with GHash.io pool getting around 50% for a short time too).

Regarding Doge I wonder how they would achieve this as it's merged-mined with Litecoin. They would need to attack LTC too in this case if I'm not wrong.

What is this all about? Qubic only targeting privacy coins instead of centralized coins like OFFICIAL TRUMP.

"Official Trump" is a Solana token so you'd need to attack Solana for that. As a highly centralized PoS coin I think this is more complicated, but not impossible. PoS is not totally bulletproof but you need other attack methods (e.g. takeover of seeding nodes).

[Kavelj22]

Kraken has already paused all Monero deposits following the recent news:  https://dailycoin.com/doge-next-kraken-freezes-monero-xmr-after-51-control-grab/ I really can't understand why such a pool would proceed in such a destructive attack despite it will be the first infected.

Now checking the price chart, it's actually arround 268$ which is can be considerable as stable despite the bad news: https://coinmarketcap.com/currencies/monero/ However i don't expect to remain in that level if more exchanges will follow Kraken.
This drove me to think why community seems not that interested with the news. In btt forum i can't find other active discussions but this topic and one published in my local board with few contrubitions.

I have just found this link from Monero official ANN thread here in bitcointalk forum: https://riat.at/reaction-coindesk-research-article-alleged-51-attack-on-monero-pow-network/
This is the important quote:

Monero was not 51% attacked. This article debunks CoinDesk’s report, revealing how Qubic’s hashrate claims were faked to mislead the crypto community.

Dear Coindesk,

We are writing you to express serious concerns about the article “Monero’s 51% Attack Problem: Inside Qubic’s Controversial Network Takeover,” published on August 12, 2025.

While the article brings an important topic to light, it appears to have uncritically published claims from Qubic, leading to the misleading conclusion that a successful 51% attack on the Monero network is underway.

This article, in its current form, is of low journalistic quality as it presents unverified claims as fact. By providing a platform for Qubic’s unproven assertions, it risks damaging the reputation of a legitimate project like Monero and causes significant concern within the broader cryptocurrency community. The alleged “attack” by Qubic is not a real 51% attack but rather a marketing stunt based on falsified numbers.

We have evidence to suggest that Qubic’s claims are misleading and their hashrate numbers are not independently verifiable. This action damages legitimate miners and network participants for the personal gain of a single entity. It is unacceptable for a reputable publication like CoinDesk to provide a stage for such bad economic actors.

[d5000]

Kraken has already paused all Monero deposits following the recent news:

This is already old news. Kraken has reenabled deposits/withdrawals, but now they're requiring a high number of confirmations (I think it was 720 or so). A bit exaggerated I think but it's ok if security comes first.

At reddit they have a thread about the current status of exchanges: https://www.reddit.com/r/Monero/comments/1muaihx/current_status_of_exchanges/

Yesterday I saw for a few minutes in the mining stats that Qubic claimed to have 51-52% of the hashrate (with ~4 GH/s) , but they weren't able to get more than 20-30 blocks from the last 100 so it was very likely only a short peak.

My advice for Monero devs would be to integrate some form of merged mining with other PoW chains (Bitcoin? But then some of them would need to stop their anti-Bitcoin shilling ...), because this may be an "attack" only for demonstration purposes, but what if some FATF-abiding governments or "sponsored" companies see a chance to really start a malicious attack?

[Dogedegen]

What is this all about? Qubic only targeting privacy coins instead of centralized coins like OFFICIAL TRUMP.

TRUMP is not even a coin, it is a token. They can't attack it this way.

Regarding Doge I wonder how they would achieve this as it's merged-mined with Litecoin. They would need to attack LTC too in this case if I'm not wrong.

Yes, that sounds correct to me. Litecoin has about 3 PH/s right now. It would be quite expensive to attempt an attack on Dogecoin this way. Is merge mining the best defense against this? What are the downsides to it?

My advice for Monero devs would be to integrate some form of merged mining with other PoW chains (Bitcoin? But then some of them would need to stop their anti-Bitcoin shilling ...), because this may be an "attack" only for demonstration purposes, but what if some FATF-abiding governments or "sponsored" companies see a chance to really start a malicious attack?

If Qubic can do this, a state sponsored entity can easily attack the chain this way.

[NotATether]

In the second one you which is the one I posted an image from, you can see that the Qubic hashrate currently is at approximately 28% of the known network hashrate. Judging from the small chart it looks however they were significantly over 40% on August 14 during some moments, maybe close but probably not over 50% (their best percentage was when they reached 3 GH/s and hashvault.pro had under-average hashrate, from a first glance it seems in these moments the other pools together had about 3.4 GH/s). They seem to have done some selfish mining and thus have orphaned some other blocks.

Qubic miners are crazy if they think they can control Monero for an extended period of time. They are the largest privacy network in the world.

Kraken has already paused all Monero deposits following the recent news:  https://dailycoin.com/doge-next-kraken-freezes-monero-xmr-after-51-control-grab/ I really can't understand why such a pool would proceed in such a destructive attack despite it will be the first infected.

Shoutout to Kraken for leaving Monero trading online for as long as they could though.

[d5000]

Is merge mining the best defense against this? What are the downsides to it?

As with merged mining you have potentially access to the hashrate and security of large coins, including Bitcoin, I think it is indeed the "best" or "most secure" PoW alternative for smaller altcoins.

One of the downsides is of course that if you have already a group of miners sustaining the chain, very likely this group will lose its business model if this implies an algorithm change and the hardware of the "traditional" miners isn't optimized for the new algo. The transition from independent mining to merged mining could have thus some potential for attackers, when the merged mining hashrate is still not fully developed. For example, if Monero introduced merged mining with Bitcoin, it would take some time until all Bitcoin miners have upgraded their software, and the "old XMR miners" during that time wouldn't be able to "help" with hashrate. Maybe a hybrid transition with both algos in parallel is possible though, but it could add complexities and perhaps new attack vectors.

And there's the problem that perhaps it isn't worth the hassle for all miners to upgrade to merged mining in the case of a large coin like Bitcoin. It could perhaps even be better for a coin like XMR to introduce merge mining with the Doge/LTC "complex", as for these miners the Monero income would be far more substantial than for Bitcoin miners.

IMO the biggest problem of merged mining is if the "hybrid hashrate" is too low, e.g. if only 10% of BTC miners merge-mine XMR, then a big Bitcoin pool could try to 51% attack the merged-mined coin, like it occurred with CoiledCoin in 2013 or so: see this Reddit thread. If instead the incentives are high enough to ensure a high "hybrid hashrate" this attack should be very difficult (this could be again easier if the merged-mined coins are all altcoins, see previous paragraph for the example with Doge/LTC).

There are also some issues with MEV, e.g. if you're merge-mining Coin A and Coin B, and there was just a block in Coin B found with a large amount of transaction fees (like the BTC halving block in 2024 where a lot of NFT guys tried to include a Rune or Ordinal transaction), then another miner could try to reorg both chains to collect these fees himself. I'm not expert enough to evaluate that risk in depth though. Sergio Demian Lerner wrote an article about disadvantages of MM here. It is focused on sidechains though.

Qubic miners are crazy if they think they can control Monero for an extended period of time. They are the largest privacy network in the world.

Currently I agree. There could be a problem however if other groups with other kinds of interests join the Qubic miners. So I would really recommend a "Plan B" to the Monero folks, some nuclear option for a "real" attack.