PSA: Qubic is lying. They don't have >50% hash rate. Don't fall for it.

As long as we as a community don't fall for it, Qubic will lose.

Qubic has been making a lot of noise over the past couple days about supposedly reaching over 50% of Monero's hashrate. This means that they can, supposedly, take control of the network through a 51% attack by orphaning all other pools' blocks.

But Qubic is bluffing.

They do not have over 50% of the network's hashrate. Their entire attack plan is to convince miners that they are capable of pulling off a 51% attack, and to use the threat of lost profits to make miners switch from other pools to theirs. If they are successful in this disinformation campaign, they might convince enough miners to switch so that they do actually have over 50% hashrate. Then, they actually could pull off a 51% attack.

Do not fall for it.

In reality, qubic had roughly 35-40% of the network's hashrate at that point. At the time of writing, it has actually declined to about 30%, but that's not the point. That's still a lot, but it's not nearly enough to do a 51% attack. They'd have needed to increase their hashrate by 50% or more in order to be capable of a 51% attack.1

Let's talk about why they were able to mine the majority of blocks despite not having the majority of hashrate. Qubic was using a technique called "selfish mining", which is basically a technique that temporarily hides your mined blocks from the rest of the network in order to gain a competitive advantage. Using this strategy, you can mine a lot higher percentage of blocks than you could by mining fairly. This is how they were able to mine the majority of blocks for a period during their previous "mining marathon" despite not having the majority of the network's hashrate. Here is a more detailed explanation.

According to MiningPoolStats and XMRWatch, at the time of Qubic supposedly surpassing 50% of the network's hashrate, all of the known non-Qubic monero pools had a combined hashrate of about 4 GH/s.2 You can verify this, though it may take some time, by manually adding up each pool's hashrate. In contrast, per Jetskipool and QubicDesciple, Qubic had about 2.5 GH/s. Meaning that Qubic had roughly 38% of the network's total hashpower (~6.5 GH/s) at that time. Even with a minority of hashrate, selfish mining still allows them way more blocks than expected, especially when they get lucky3:

Qubic shills keep spamming that they now have 51% of the network in their palm, and that miners need to switch over now to avoid losing money. But the reason they're so desperate for miners is switch is precisely because they don't have 51% of the network's hashpower, but want to have it in time for the attack.

As for why sites like Jetskipool were showing >50% network share at that time, their calculated total network hashrate (less than 5 GH/s) was inaccurate for two reasons. First, that total is a moving average, and takes time to adjust when they turned their miners back on, meaning that the estimate was much lower (and their percentage much higher) than it actually was. Secondly, and more importantly, due to selfish mining, a lot of both Qubic and non-Qubic blocks were never included in the blockchain due to failed or successful selfish mining incidents, respectively. Since they were never included in the blockchain, these blocks' work is not added to the total estimated network hashrate, again making their share of the network's total hashrate appear much higher than it actually was. The Qubic devs are aware of these factors, but their attack relies on people not knowing this. Sites like these are what they use to lie. It's all part of their scare tactic.

This attempted attack is not sustainable. Qubic is burning a lot of money on this, and it has a halving in just over a week from now, which will cripple its ability to keep payrolling it. That doesn't mean we'll be out of the woods, but they're currently at the height of their power, which is why they're so desperate to pull off an attack in time. They weren't even able to maintain their selfish mining! During their most recent "Monero mining marathon", the one where they claim they achieved 51% of hashrate, they actually only mined about 36% of blocks total.

Qubic will only win if people believe their lies.

Don't fall for it.

With that all being said, they are still a threat. They can only win if they're able to convince enough miners that they've already won, which they haven't. If you aren't already, start mining solo, on p2pool, or really any other pool besides Qubic.

Notes:

This is more than you'd think, since increasing their hashrate also increases the network's total hashrate. Think of it like this: Assume they had 40% of the network's hashrate, meaning they had 4 out of 10 "shares" of the network's hashrate, meaning that all other miners combined had 6. They would need to surpass those 6 shares' worth, which is about 50% higher than their 4. If they were to obtain 2 extra shares, then the network would have had 12 shares total, leaving them with 50% of the total hashrate. If we instead assume that they have 30% hashrate (this is the case at the time of writing), then they acutally need more than double their current hashrate.

Qubic shows up as "unknown" on MiningPoolStats, because they stopped publicly reporting their hashrate. They specifically did this to obfuscate how much hash power they really have. Qubic's hashrate is still available through the other sources mentioned, but they want to avoid it being easily visible and comparable to other pools, since that would expose their lies.

Random variation plays a huge role in mining, meaning that miners can find way more or way less blocks than expected over a short enough timeframe. Qubic's luck in any given 100 block window varied wildly from 21% up to the high 40's percent. Either way, they are not even close to sustaining a 51% attack.