Quantum Threat to Bitcoin: Why the Risk Is Overestimated According to CoinShares

📋 En bref (TL;DR)

Risk overestimated: CoinShares estimates that only 10,200 BTC would truly be at risk, not 20-50% of the supply
Scattered targets: Potentially vulnerable bitcoins are spread across 32,000+ wallets averaging 50 BTC each
Distant technology: It would take quantum computers 100,000 times more powerful than today’s
Estimated timeline: At least a decade before a real threat, according to experts
Solutions underway: BIP-360 and post-quantum signatures in preparation
P2PK addresses: Only old address formats (1.6M BTC) are theoretically exposed

Is the quantum threat Bitcoin’s Achilles’ heel? A new report from CoinShares, one of the largest digital asset managers in the world, provides a nuanced answer: the risk exists, but it is much smaller than alarmist estimates suggest.

Analysis of a threat that sounds scary, but might be more manageable than you think.

Debunking the Alarmist Numbers

You often read that 20% to 50% of all bitcoins would be vulnerable to quantum attacks. CoinShares, which manages over $10 billion in assets and holds 34% of the European crypto ETP market, disputes these estimates.

The Real Exposure: 8% of Supply

The analysis focuses on P2PK (Pay-to-Public-Key) addresses, an old format where the public key is permanently visible on the blockchain. These addresses are the only ones truly vulnerable because a quantum computer could theoretically derive the private key from them.

CoinShares estimates that approximately 1.6 million BTC (8% of total supply) are held in these legacy addresses. That’s already far less than the 20-50% often cited.

But Only 10,200 BTC at « Real Risk »

Here’s where the analysis gets really interesting. Among these 1.6 million BTC, how many could actually be stolen in a way that would « disrupt the market »?

CoinShares’ answer: approximately 10,200 BTC.

Why? Because the rest is scattered across more than 32,000 different UTXOs, averaging 50 BTC each. A quantum attacker would need to:

Crack each address one by one
Spend considerable time on each wallet
Accumulate relatively small gains each time

It’s not like hacking a single address and walking away with billions.

The Technological Horizon: At Least a Decade

Beyond the question « how many BTC are exposed? », there’s the question of « when? ». And experts are clear: not anytime soon.

The Numbers That Matter

Charles Guillemet, CTO of Ledger (cited in the report), provides these benchmarks:

Google Willow (best current quantum computer): 105 qubits
Required to break Bitcoin: several million qubits
Technology gap: factor of 100,000x

CoinShares estimates that fault-tolerant quantum systems, approximately 100,000 times more powerful than current machines, would be required. This places the real threat at at least a decade away.

What Bitcoin Developers Say

Most Bitcoin developers consider quantum risk a « non-issue » in the short term. In December 2025, CoinDesk reported that the technical community views this threat as distant — decades, not years.

Solutions in Preparation

Even though the threat is distant, the Bitcoin ecosystem is not sitting idle.

BIP-360: The Progressive Migration

The BIP-360 proposal aims to introduce new wallet formats with post-quantum signatures. The idea is to allow users to progressively migrate to addresses resistant to quantum attacks.

The Debate on Preparedness

A point of friction exists within the community:

Developers believe they have time and prefer well-thought-out solutions
Institutional investors want concrete plans and a clear timeline

CoinShares concludes that quantum risk is not an emergency, but a « predictable engineering problem » that Bitcoin can absorb over time.

Why Is This Topic Resurfacing Now?

Discussions about the quantum threat periodically resurface, often during market downturns. Investors then look for structural explanations for price movements.

The reality is more prosaic: advances from Google, IBM, and others in quantum computing regularly make headlines, which reignites speculation about Bitcoin.

Key Takeaways

For the average crypto investor, here are the key points:

Don’t panic: The threat is real but distant (10+ years)
Use modern addresses: P2PKH and P2SH formats (starting with 1 or 3) and SegWit addresses (bc1) are safer than old P2PK addresses
Follow developments: The Bitcoin community is working on solutions
Diversify: As with any risk, don’t put all your eggs in one basket

📚 Glossary

Bitcoin: The first cryptocurrency, using elliptic curve cryptography (ECDSA) to secure transactions.
P2PK: Pay-to-Public-Key, an old Bitcoin address format where the public key is directly visible on the blockchain. More vulnerable to quantum attacks.
Blockchain: A distributed and immutable ledger recording all Bitcoin transactions.
UTXO: Unspent Transaction Output, represents a « piece » of unspent bitcoin associated with an address.
Post-quantum signature: A cryptographic signature algorithm designed to resist attacks from quantum computers.
Qubit: The basic unit of quantum information, equivalent to a bit in classical computing but capable of existing in multiple states simultaneously.

Frequently Asked Questions

Can quantum computers hack Bitcoin?

In theory, a sufficiently powerful quantum computer could derive private keys from Bitcoin addresses whose public key is exposed. But current machines are about 100,000 times too weak to do so. Experts estimate this threat at least a decade away.

How much Bitcoin is really at risk?

According to CoinShares, approximately 1.6 million BTC (8% of supply) are in potentially vulnerable legacy addresses. But among these, only 10,200 BTC represent targets large enough to « disrupt the market. » The rest is scattered across 32,000+ small wallets.

Is my Bitcoin in danger?

If you use a modern wallet (addresses starting with 1, 3, or bc1), your public key is only exposed at the time of an outgoing transaction. The risk is therefore minimal. P2PK addresses (very old) are the most vulnerable.

What is the Bitcoin community doing to protect itself?

Proposals like BIP-360 aim to introduce post-quantum signatures, enabling a progressive migration to resistant addresses. Developers prefer well-thought-out solutions rather than a hasty reaction.

When will quantum computers be powerful enough?

Google Willow, the best current quantum computer, has 105 qubits. Breaking Bitcoin would require several million qubits. CoinShares and Ledger estimate this technological advancement at least 10 years away, probably more.

📰 Sources

This article is based on the following sources:

How to cite this article: Fibo Crypto. (2026). Quantum Threat to Bitcoin: Why the Risk Is Overestimated According to CoinShares. Retrieved February 9, 2026 from https://fibo-crypto.fr/en/blog/quantum-threat-bitcoin-coinshares-risk-overestimated

Quantum Threat to Bitcoin: Why the Risk Is Overestimated According to CoinShares