What to know:

• Project Eleven has launched the Q-Day Prize, offering 1 bitcoin to the first team to break an elliptic curve cryptographic key using a quantum computer.
• The competition underscores the looming threat that quantum computing poses to Bitcoin’s security, with over 10 million addresses at risk.
• Initiatives like the Quantum-Resistant Address Migration Protocol and Coarse-Grained Boson Sampling have been suggested, both requiring a hard fork.

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Project Eleven, a quantum computing research and advocacy organization, has initiated the Q-Day Prize, a worldwide challenge that offers 1 bitcoin (BTC) to the first group that successfully breaks an elliptic curve cryptographic (ECC) key with Shor’s algorithm on a quantum computer.

Shor’s algorithm is a quantum computational technique that allows for the efficient factorization of large numbers into their prime factors, theoretically enabling quantum computers to dismantle cryptographic measures like RSA and the elliptic-curve cryptography utilized in Bitcoin and other blockchain systems.

“We just launched the Q-Day Prize. 1 BTC to the first team to break a toy version of Bitcoin’s cryptography using a quantum computer. Deadline: April 5, 2026 Mission: Protect 6M BTC (over $500B)” — Project 11 (@qdayclock) April 16, 2025

The competition is timely, as advancements in quantum computing may lead to the realization of a functional quantum computer within mere years. Furthermore, Project Eleven has identified over 10 million bitcoin addresses with non-zero balances that could fall victim to quantum assaults.

The Bitcoin community is increasingly aware of the quantum computing threat and is actively exploring protective measures.

As previously reported by CoinDesk, a Bitcoin Improvement Proposal (BIP) named the Quantum-Resistant Address Migration Protocol (QRAMP) was introduced in early April, advocating for a network-wide migration to post-quantum cryptography to shield Bitcoin wallets. However, implementing such a change would necessitate a hard fork, and achieving consensus on this matter could prove challenging.

Additionally, the quantum-focused startup BTQ has presented its solution: a quantum alternative to Bitcoin’s Proof of Work known as Coarse-Grained Boson Sampling (CGBS).

CGBS leverages quantum technology to cultivate unique patterns of bosons (light particles) and aims to replace conventional mining tasks with quantum-centric sampling challenges for validating transactions. However, similar to BTQ’s CGBS, this strategy would also require a hard fork, and the community’s appetite for such a change remains uncertain.