Key Takeaways
- Independent researcher Giancarlo Lelli successfully cracked a 15-bit elliptic curve encryption key with quantum computing technology, securing a 1 BTC reward from Project Eleven
- This represents the most significant publicly documented quantum attack against elliptic curve cryptography in history
- Bitcoin relies on 256-bit encryption keys — substantially more complex than the compromised 15-bit key, though the technology gap continues to shrink
- Approximately 6.9 million BTC stored in addresses with visible public keys may face vulnerability from advanced quantum computing in the future
- Security experts remain divided on timing — projections range from several years to multiple decades before quantum technology becomes a legitimate security concern
Giancarlo Lelli, working independently, has successfully compromised a 15-bit elliptic curve encryption key utilizing publicly available quantum computing resources. For this accomplishment, Project Eleven — a startup focused on post-quantum security solutions — presented him with a bounty of 1 BTC, valued at more than $78,000.
Project Eleven described the achievement as the “largest quantum attack” against elliptic curve cryptography ever documented in the public domain.
Lelli employed a modified version of Shor’s algorithm to extract a private key from its corresponding public key, searching through 32,767 potential values. Shor’s algorithm specifically exploits the mathematical foundations that protect digital signatures across Bitcoin, Ethereum, and numerous other blockchain networks.
Prior to Lelli’s breakthrough, engineer Steve Tippeconnic successfully compromised a 6-bit elliptic curve key in September 2025 using IBM’s 133-qubit quantum processor. Lelli’s 15-bit achievement represents an expansion by a factor of 512.
Bitcoin employs 256-bit elliptic curve cryptography for security. While a substantial difference exists between this and the 15-bit key Lelli compromised, Project Eleven emphasizes that the gap is “increasingly viewed as an engineering problem and not a fundamental physics problem.”
“The resource requirements for this type of attack keep dropping, and the barrier to running it in practice is dropping with them,” explained Alex Pruden, CEO of Project Eleven.
Quantifying the Potential Bitcoin Exposure
According to Project Eleven’s analysis, approximately 6.9 million Bitcoin currently reside in wallet addresses where public keys remain exposed on the blockchain. These holdings could become susceptible should quantum computing capabilities advance sufficiently.
Bernstein analysts estimate roughly $450 billion worth of Bitcoin sits in legacy wallet addresses featuring exposed public keys.
The danger remains theoretical at present. Existing quantum systems fall considerably short of the computational power required to compromise production-grade cryptographic protections.
Research published by Google suggests that breaking 256-bit elliptic curve encryption might require fewer than 500,000 physical qubits. Subsequent research from the California Institute of Technology in collaboration with quantum firm Oratomic proposed the threshold could be as minimal as 10,000 qubits.
Industry Response and Preparation
Bitcoin core developers have already proposed transition strategies toward post-quantum cryptographic standards. Ethereum, Tron, StarkWare, and Ripple have similarly announced related defensive initiatives.
Speaking at Paris Blockchain Week in April, Blockstream CEO Adam Back stressed that preparation should commence immediately, regardless of whether the actual threat materializes in decades. “Quantum computing still has a lot to prove. Current systems are essentially lab experiments,” Back stated.
Bernstein has recommended measured responses, characterizing quantum computing as a medium to long-term infrastructure evolution rather than an urgent crisis.
According to Bernstein’s research, the Bitcoin development community generally operates under a three to five-year preparation timeframe.
Project Eleven, which counts Castle Island Ventures, Coinbase Ventures, and Variant among its investors, secured $20 million in Series A funding earlier this year, achieving a $120 million post-money valuation.
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