The Bitcoin (BTC) network now faces the largest quantum threat after a researcher cracked a 15-bit elliptic curve cryptography (ECC) key on a publicly accessible quantum computer.
On April 24, Project Eleven, a quantum computing research organization, awarded 1 BTC to independent researcher Giancarlo Lelli after he successfully derived a private key from its public key across a search space of 32,767 possible combinations. Lelli used cloud-based quantum hardware available to the general public to crack the 15-bit ECC.
The previous public demonstration of such an attack class was a 6-bit break, achieved in September 2025 by Steve Tippeconnic. As such, the possibility of a quantum attack on Bitcoin surged 512-fold in 8 months.
What does this ECC attack mean for Bitcoin?
Notably, every Bitcoin wallet uses a private key, a unique 256-bit number that is mathematically related to its public key. As such, the break of 15-bit ECC is not an immediate threat to BTC, but a notable leap in less than a year.
Google researchers previously estimated that a strong enough quantum computer could break the Elliptic Curve Discrete Logarithm Problem (ECDLP) by 2029. Furthermore, Google predicted that a capable quantum computer could intercept a Bitcoin transaction by decoding its private keys from the public key in 9 minutes, before the 10-minute confirmation time, by 2029.
With roughly 6.9 million Bitcoin, valued at approximately $534.3 billion at press time, held in wallets whose public keys are publicly visible, Project Eleven highlighted the need for blockchains to transition to post-quantum encryption. Moreover, the leap from 15-bit to 256-bit is an engineering headwind that could progress faster than expected.
Currently, Project Eleven is developing its next challenge, focusing on the intersection of top-tier artificial intelligence (AI) models and quantum cryptanalysis.
Source: https://finbold.com/bitcoin-faces-largest-quantum-threat-yet-as-a-new-attack-is-confirmed/
