TLDR
- Giancarlo Lelli successfully compromised a 15-bit elliptic curve cryptographic key through quantum computing, earning a 1 BTC reward from Project Eleven
- The achievement represents the most significant publicly documented quantum assault on elliptic curve encryption
- Bitcoin employs 256-bit keys, substantially exceeding the 15-bit key that was compromised, though experts note the distance between them continues to shrink
- Approximately 6.9 million BTC stored in wallets with visible public keys face potential vulnerability from advanced quantum attacks
- Security experts remain split on timing—estimates range from several years to multiple decades before quantum technology becomes a genuine security concern
Giancarlo Lelli, working independently, has successfully compromised a 15-bit elliptic curve cryptographic key through quantum computing technology available to the public. The achievement earned him a 1 BTC reward from Project Eleven, a startup focused on post-quantum security solutions—a prize valued above $78,000.
Project Eleven Awards 1 BTC Q-Day Prize for Largest Quantum Attack on Elliptic Curve Cryptography to Date
Researcher breaks 15-bit ECC key on publicly accessible quantum hardware in a 512x jump from the previous public demonstration.
Project Eleven today awarded the Q-Day…
— Project Eleven (@projecteleven) April 24, 2026
According to Project Eleven, this represents the most substantial quantum assault on elliptic curve cryptography documented in the public domain.
Lelli employed a modified version of Shor’s algorithm to extract a private key from its corresponding public key within a computational space containing 32,767 potential values. Shor’s algorithm specifically exploits the mathematical foundations securing digital signatures across Bitcoin, Ethereum, and the majority of blockchain networks.
Prior to Lelli’s accomplishment, engineer Steve Tippeconnic achieved a breakthrough with a 6-bit elliptic curve key during 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 cryptography for security. The distance between this standard and the 15-bit key Lelli compromised remains substantial. However, Project Eleven characterizes this gap as something “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.
How Much Bitcoin Is at Risk?
According to Project Eleven’s analysis, approximately 6.9 million Bitcoin reside in wallet addresses where public keys have been exposed on the blockchain. These holdings face potential vulnerability should quantum computing capabilities advance sufficiently.
Analysts at Bernstein estimate the value at roughly $450 billion in Bitcoin, concentrated in legacy wallet addresses with public key exposure.
The timeline for any practical threat remains distant. Contemporary quantum systems fall considerably short of the capabilities required to compromise production cryptographic systems.
Research published by Google estimates that compromising 256-bit elliptic curve cryptography might demand under 500,000 physical qubits. Subsequent research from the California Institute of Technology working alongside quantum startup Oratomic proposed the threshold could drop to approximately 10,000 qubits.
What the Industry Is Doing
Bitcoin’s development community has begun drafting migration strategies toward post-quantum cryptographic standards. Similar initiatives have been announced by Ethereum, Tron, StarkWare, and Ripple.
Blockstream CEO Adam Back stated at Paris Blockchain Week in April that proactive preparation makes sense today, regardless of whether the actual threat materializes in decades. “Quantum computing still has a lot to prove. Current systems are essentially lab experiments,” Back said.
Bernstein has recommended measured responses, framing quantum computing as a medium to long-term infrastructure evolution rather than an urgent crisis.
According to Bernstein analysts, the Bitcoin community generally operates with a three to five-year preparation horizon.
Project Eleven, supported by Castle Island Ventures, Coinbase Ventures, and Variant, secured $20 million during a Series A funding round earlier this year, achieving a $120 million post-money valuation.
