Is the threat of quantum computing to Bitcoin overestimated? ARK Invest illustrates a five-stage progressive risk chart

ARK Invest and Unchained jointly released the latest white paper, systematically refuting the market narrative of “Quantum Day” (Q Day). The white paper states that the risk of quantum computing compromising Bitcoin will not impact the market through a single sudden event but will instead evolve gradually through foreseeable technological advancements. The core conclusion of the report is clear: Bitcoin currently does not face an immediate threat from quantum computing.

Five-Stage Framework: How Quantum Threats Evolve from Zero to Critical Point

(Source: Ark Invest)

The five-stage roadmap proposed by ARK Invest and Unchained provides a systematic framework to track the development of quantum computing technology from commercial beginnings to cryptographic threats:

Stage 0 (Current): Quantum computers exist but have no commercial applications. Today’s technology is in the “NISQ era”—about 100 logical qubits, circuit depths of a few hundred quantum gates—far below the minimum threshold needed to crack Bitcoin’s elliptic curve cryptography (ECC): at least 2,330 logical qubits and tens of millions to billions of quantum gates.

Stage 1: Quantum systems achieve commercial applications in specific industries such as chemistry and materials science but are unrelated to cryptocurrencies.

Stage 2: Quantum technology can crack weak keys or outdated cryptosystems. This is the first practical threat posed by cryptographically relevant quantum computers (CRQC), targeting the most vulnerable systems rather than Bitcoin’s 256-bit ECC.

Stage 3: Bitcoin faces its first real risk—ECC could theoretically be cracked, but the process would still take a long time. Bitcoin stored before 2011 with P2PK addresses (whose public keys have long been exposed) is more vulnerable, while modern address formats provide stronger resistance against quantum attacks.

Stage 4: Critical tipping point. When quantum computers can crack private keys faster than Bitcoin’s 10-minute block time, and if no protocol-level actions are taken, Bitcoin will face a “serious threat as a useful monetary system—posing a survival threat to the protocol itself.”

Post-Quantum Cryptography (PQC) Is Already Ahead

The report highlights a key reassuring finding: current progress in post-quantum cryptography (PQC) is ahead of the development of CRQCs capable of cracking Bitcoin encryption. Proposals for quantum-secure Bitcoin addresses (such as BIP-360) already exist, and stakeholders with vested interests in the network have strong incentives to implement protective measures when necessary.

Three Scenarios and a Reasonable 10- to 20-Year Time Frame

The report also presents three possible timelines for threat realization:

Pessimistic Scenario (Sudden Breakthrough): An unexpected leap in quantum technology catches the Bitcoin community off guard. However, the report believes Bitcoin can still survive because multiple PQC proposals can be rapidly deployed under pressure.

Optimistic Scenario (Technological Stagnation): Quantum computing faces long-term stagnation due to physical and engineering barriers, giving Bitcoin ample time to advance research, testing, and upgrades.

Balanced Scenario (Mainstream Prediction): Quantum computers reach Stage 3 within 10 to 20 years. The report suggests that within this timeframe, the PQC research community will achieve enough algorithm breakthroughs to give Bitcoin developers sufficient time to complete adaptive upgrades.

Frequently Asked Questions

Why does ARK Invest believe there will be no sudden “Q Day” event?

The “Q Day” hypothesis assumes a sudden leap in quantum computing technology capable of breaking all existing encryption without warning. However, ARK Invest’s analysis indicates that progress in quantum computing follows observable physical and engineering paths, with each threat stage showing precursors (such as incremental improvements in qubit count and error rates), providing markets and protocols with enough time to react.

Do Bitcoin holders need to take any action now?

The report suggests no urgent action is necessary at present. Most modern Bitcoin addresses (like P2WPKH, P2TR) already have some quantum resistance; the higher risk lies with addresses created before 2011 (P2PK), whose public keys have been exposed for a long time. Holders of such old addresses may consider migrating to modern address formats.

How long would it take to upgrade the Bitcoin protocol to post-quantum security?

The co-author of BIP-360 previously estimated that a full post-quantum upgrade could take about seven years. ARK Invest and Unchained’s report believe that, under the balanced scenario, the timeline for quantum computers to reach the technological level that poses a real threat to Bitcoin is 10 to 20 years, leaving enough time for the Bitcoin development community to implement necessary upgrades—provided the upgrade efforts are initiated and advanced in a timely manner.