Breakthrough in Quantum Attack: Researcher Claims 1 Bitcoin Bounty

The theoretical threat of quantum attacks on cryptocurrency has become more tangible, as independent researcher Giancarlo Lelli has successfully broken a 15-bit elliptic curve key on publicly accessible quantum hardware. This achievement has earned him a 1 bitcoin bounty, worth approximately $78,000, as part of the Q-Day Prize awarded by quantum security startup Project Eleven. The breakthrough demonstrates the largest public demonstration of a quantum attack on elliptic curve cryptography to date, sparking concerns about the potential vulnerability of major blockchains, including Bitcoin and Ethereum. Elliptic curve cryptography is a crucial component of cryptocurrency wallets, enabling them to prove ownership of funds without revealing private keys. However, quantum computers utilizing Shor's algorithm can potentially compromise this security. Lelli's achievement, while significant, does not pose an immediate threat to Bitcoin, as it uses 256-bit elliptic curve security, far more complex than the 15-bit key broken by Lelli. The previous public demonstration, conducted by Steve Tippeconnic in September 2025, involved a 6-bit key, and Lelli's result represents a 512-fold increase in complexity. The rapid progress in quantum attacks has led to a decrease in estimated resource requirements, with a recent Google Research paper suggesting that a full 256-bit attack could be possible with fewer than 500,000 physical qubits. This development has heightened concerns among cryptocurrency developers, with roughly 6.9 million bitcoin, approximately one-third of the total supply, potentially vulnerable to quantum attacks. In response, Bitcoin developers have proposed migration paths, including the implementation of quantum-safe address types, while other blockchain platforms, such as Ethereum and Ripple, have also published post-quantum transition plans.