An independent researcher successfully cracked a 15-bit elliptical crypto key on a publicly available quantum computer, winning a prize of 1 Bitcoin. This breakthrough, 512 times more powerful than the previous one, poses an urgent question: are blockchains really ready for the quantum era?
In brief
- An independent researcher cracked a 15-bit elliptical key on a cloud-accessible quantum computer.
- This breakthrough, 512 times more powerful than the previous record, reduces estimates for cracking 256-bit keys to less than 500,000 qubits.
- 6.9 million bitcoins (1/3 of the supply) are vulnerable if blockchains do not quickly migrate to post-quantum algorithms.
Researcher breaks crypto key with quantum computer
According to Vitalik Buterin, crypto has until 2028 to avoid quantum collapse. Except that Giancarlo Lelli, an independent researcher, has just made history by breaking a 15-bit elliptical crypto key on quantum hardware available via the cloud! Proving that quantum attacks are no longer reserved for ultra-specialized laboratories. This demonstration, rewarded by the Q-Day Prize (1 Bitcoin), exceeds the previous record established in September 2025 by 512 times. In fact, Lelli exploited a variant of Shor's algorithm, targeting the discrete logarithm on elliptic curve problem (ECDLP), the basis of the digital signatures securing Bitcoin and Ethereum.
Contrary to theoretical attacks, this progress shows that the quantum threat becomes tangible, even with limited resources. This success highlights a worrying trend. In particular, the collapse of costs and technical barriers to breaking crypto keys. A Google study, published in April 2026, now estimates that an attack on a 256-bit key (current standard) would require less than 500,000 qubits, compared to millions previously.
Bitcoin in danger from the quantum computer?
Although Bitcoin uses 256-bit keys, this advance raises fears about the long-term security of blockchains. Around 6.9 million bitcoins (a third of the total supply) are stored in crypto addresses whose public keys are visible on-chain, making them vulnerable to a future quantum attack. For experts, the immediate risk remains limited, but the exponential progression of quantum capabilities requires a rapid reaction.
To this end, solutions such as BIP-360 (Bitcoin) or plans to migrate Ethereum to post-quantum algorithms are underway. These proposals aim to replace ECC signatures with robust alternatives, such as signatures based on Euclidean networks. For Alex Pruden, CEO of Project Eleven, the window to act is closing. Blockchains must accelerate their transition, or risk seeing billions of dollars of funds exposed to quantum attacks within a few years.
Lelli's advance proves that the quantum threat is no longer theoretical. Although bitcoin has already anticipated the quantum threat, blockchains must innovate quickly to avoid a crisis of confidence. This discovery raises crucial questions… Can blockchains migrate to post-quantum algorithms in time? Are crypto users ready to adopt more complex solutions?
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