Bitcoin News Today: "Qubic's Mining Gambit: Can Proof-of-Work Survive the 51% Shadow?"

Bitcoin hashrate concentration has become a focal point of concern as recent developments suggest two mining pools could collectively control over 51% of the network’s computing power. While the immediate threat pertains to altcoins like Monero and Dogecoin, the broader implications for Bitcoin’s security model have triggered heightened scrutiny. Monero, which relies on a proof-of-work consensus mechanism, recently experienced a controversial event where the Qubic mining pool reportedly gained control of over 37% of its hashrate. According to MiningPoolStats, Qubic's hashrate peaked at 2.32 gigahashes per second (GH/s) compared to Monero's total hashrate of 6.25 GH/s during the period [2]. Analysts have debated whether this represents a true 51% attack or a statistical anomaly exacerbated by a “selfish mining” strategy, in which blocks are withheld to create a misleading impression of dominance [2]. The Qubic community has now turned its focus to Dogecoin, another proof-of-work asset with a market capitalization exceeding $35 billion [1].

The central issue lies in the vulnerability of proof-of-work blockchains to hashrate concentration. A mining pool controlling more than half the network’s computing power can, in theory, manipulate the blockchain by altering transaction confirmations or reversing transactions. This is particularly concerning for cryptocurrencies with smaller hashrate distributions, where the barrier to entry for a potential attacker is lower. The Qubic group, led by IOTA co-founder Sergey Ivancheglo, has previously demonstrated this capability with Monero, and its move to target Dogecoin signals a potential trend of strategic attacks aimed at exploiting network weaknesses [1]. Researchers from the RIAT Institute, however, have contested the narrative, arguing that the alleged hashrate dominance over Monero did not breach the 51% threshold when accounting for solo miners and potential data inaccuracies [2].

Despite the controversy, the incident has prompted exchanges to take precautionary measures. Kraken, for instance, temporarily suspended Monero deposits, though it kept XMR trading and withdrawals open, citing a need for additional clarity on the network’s security [1]. This response highlights the balancing act exchanges must perform between user trust and operational continuity during such events. The broader cryptocurrency ecosystem has also taken notice, with industry experts emphasizing the importance of decentralized hashrate distribution to prevent similar scenarios from unfolding on larger blockchains like Bitcoin.

Bitcoin, which remains the largest proof-of-work blockchain by hashrate, has seen its mining landscape evolve with the rise of centralized mining pools. While Bitcoin's hashrate is significantly higher than Monero's or Dogecoin's, a concentration of mining power within a small number of pools could still pose systemic risks. The Bitcoin hashrate is currently distributed among several major pools, but recent patterns show a narrowing of control. A 2025 analysis of Bitcoin mining pools noted a growing reliance on a handful of dominant players, which could make the network susceptible to strategic coordination or external pressures [3]. While no single pool has yet claimed over 50% of Bitcoin’s hashrate, the potential for such a scenario underscores the importance of maintaining a decentralized mining environment.

The debate surrounding the Qubic attacks and Monero’s hashrate dynamics has also highlighted the need for improved transparency and verification mechanisms. Researchers from RIAT and other entities have called for greater accountability in how hashrate data is reported, emphasizing that metrics can be manipulated through tactics like block withholding. In Monero’s case, the absence of verifiable on-chain evidence—such as a published view key—has led many to question the true extent of Qubic’s influence. This lack of clarity has sparked calls for enhanced protocol-level safeguards to prevent misleading interpretations of hashrate dominance and to ensure that the integrity of proof-of-work systems remains intact.

Source:

[1] Monero's 51% Attacker, Qubic, to Target DOGE Next (https://cointelegraph.com/news/qubic-monero-51percent-attacker-target-doge-next)

[2] Researchers Debunk Alleged 51% Attack on Monero (https://forklog.com/en/researchers-debunk-alleged-51-attack-on-monero/)

[3] Best Bitcoin Mining Pools in 2025 (https://koinly.io/blog/best-bitcoin-mining-pools/)