13.08.2025 06:10
Monero, a cryptocurrency prioritizing user privacy, is grappling with an unprecedented security threat. A project spearheaded by Sergey Ivancheglo, co-founder of IOTA, known as Qubic, has publicly declared control over a majority of the Monero network's hash rate, exceeding 51%. This significant power imbalance raises serious concerns about the blockchain's integrity and security.
This level of control, within a proof-of-work system mirroring Bitcoin's security model, grants Qubic the ability to manipulate the transaction history. They could potentially reverse past transactions, prevent legitimate payments from being processed, or even execute double-spending attacks, undermining the fundamental trust underpinning Monero's functionality. Qubic's justification, presented as an "experiment" in their blog post, frames their actions as a "strategic, and at times combative, application of game theory," a claim that has ignited considerable debate within the cryptocurrency community. The incident challenges established notions of Monero's decentralization and resilience.
A 51% attack exploits the inherent competition within proof-of-work blockchains. Miners race to add transaction blocks; a single entity controlling over half the computational power dominates this race. This dominance allows the attacker a wide array of malicious actions. This includes "reorgs," where confirmed blocks are replaced with manipulated ones. Equally concerning are double-spending attacks, enabling the fraudulent reuse of the same funds. However, the most impactful consequence is arguably transaction censorship, the ability to block specific payments from being confirmed—a particularly troubling prospect given Monero's privacy-focused nature. Past instances of 51% attacks on other cryptocurrencies, such as Ethereum Classic in 2020 and Bitcoin Gold in 2018 and 2020, resulting in substantial financial losses, demonstrate the very real and damaging potential of such exploits. Smaller cryptocurrencies like Verge have also suffered from similar attacks leading to significant instability.
Monero's vulnerability stems, ironically, from its attempts to maintain decentralization. Its use of the RandomX algorithm aimed to prevent the dominance of specialized mining hardware (ASICs) by encouraging CPU mining. This strategy, designed to foster a more distributed network, has seemingly been circumvented by Qubic's swift accumulation of hash rate. The rapid ascent of Qubic’s influence underscores the challenges inherent in balancing security and decentralization within a proof-of-work system. The situation highlights the ongoing need for robust security measures and a deeper understanding of the potential vulnerabilities within decentralized systems.
