Key Takeaways
- Independent researcher Giancarlo Lelli successfully cracked a 15-bit elliptic curve cryptographic key with quantum computing technology, securing a 1 BTC reward from Project Eleven
- The breakthrough represents the most significant publicly documented quantum assault on elliptic curve encryption systems
- While Bitcoin employs 256-bit encryption — substantially stronger than the compromised 15-bit key — experts warn the technological gap is closing
- Approximately 6.9 million BTC stored in addresses with publicly visible keys face potential vulnerability to advanced quantum computing attacks
- Security specialists remain split on timing — projections range from several years to multiple decades before quantum technology poses genuine danger
Giancarlo Lelli, working independently, has successfully compromised a 15-bit elliptic curve encryption key utilizing publicly available quantum computing infrastructure. For this accomplishment, Project Eleven — a startup focused on post-quantum security solutions — granted him a bounty of 1 BTC, valued at more than $78,000.
According to Project Eleven, this achievement marks the “largest quantum attack” against elliptic curve cryptographic systems ever publicly documented.
Lelli employed a modified version of Shor’s algorithm to extract the 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 the majority of blockchain networks.
Prior to Lelli’s breakthrough, engineer Steve Tippeconnic had compromised a 6-bit elliptic curve key in September 2025 utilizing IBM’s 133-qubit quantum processor. Lelli’s achievement represents a 512-fold expansion beyond that milestone.
Bitcoin relies on 256-bit elliptic curve cryptographic protection. While this represents a substantial distance from the 15-bit key Lelli defeated, Project Eleven maintains that this 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,” said Alex Pruden, CEO of Project Eleven.
Quantifying Bitcoin’s Exposure
Project Eleven calculates that approximately 6.9 million Bitcoin remain in digital wallets where public cryptographic keys have been exposed through blockchain transactions. These holdings could face compromise should quantum computing capabilities advance sufficiently.
Bernstein analysts estimate this exposure represents roughly $450 billion worth of Bitcoin secured in legacy wallet formats with visible public keys.
The danger remains theoretical at present. Contemporary quantum computing systems fall substantially short of the computational power required to compromise production-grade cryptographic protections.
Researchers at Google published findings suggesting that defeating 256-bit elliptic curve encryption might demand fewer than 500,000 physical qubits. Subsequent research from the California Institute of Technology in collaboration with quantum developer Oratomic proposed the threshold could drop to approximately 10,000 qubits.
Industry Response and Preparation
Bitcoin core developers have begun proposing transition strategies toward quantum-resistant cryptographic frameworks. Ethereum, Tron, StarkWare, and Ripple have similarly announced preliminary defense initiatives.
Blockstream CEO Adam Back emphasized at Paris Blockchain Week in April that preparatory measures should commence immediately, regardless of whether the actual threat materializes in years or decades. “Quantum computing still has a lot to prove. Current systems are essentially lab experiments,” Back said.
Bernstein analysts have recommended measured responses, characterizing quantum computing advancement as a medium-to-long-term technological transition rather than an imminent crisis.
According to Bernstein’s assessment, the Bitcoin development community generally estimates a three-to-five-year preparation window.
Project Eleven, supported by Castle Island Ventures, Coinbase Ventures, and Variant, secured $20 million through a Series A funding round earlier this year, achieving a $120 million post-money valuation.
