Ark Invest warns ~35% of Bitcoin could face future quantum risk; threat is years away and upgrades can mitigate exposure.
Ark Invest says one third of Bitcoin supply could face future quantum risk, according to a new research paper published with Unchained.
The report explains that most Bitcoin remains protected today, yet a portion could become vulnerable if quantum computing advances.
Researchers note that the threat is still years away. They also state that the Bitcoin network has time to prepare technical defenses.
Part of Bitcoin Supply Linked to Potential Quantum Exposure
The paper estimates that about 35% of the Bitcoin supply may face exposure if quantum computing breaks current cryptography.
This portion includes coins stored in older address formats or addresses that reused public keys.
These addresses reveal cryptographic data that could become vulnerable in future scenarios.
Researchers estimate that around 1.7 million BTC remain in Pay to Public Key addresses.
These addresses were used in the earliest days of the Bitcoin network. Many analysts believe a large portion of these coins may already be lost.
In collaboration with @unchained, ARK Invest's new paper on Bitcoin and Quantum computing is live!
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Bitcoin and Quantum Computing
This paper assesses whether and how advances in quantum computing (QC) pose a risk to Bitcoin. Our two central arguments are as follows:
1.… https://t.co/3qh3YGriCi pic.twitter.com/XVnQGLgyvt
— David Puell (@dpuellARK) March 12, 2026
Another 5.2 million BTC sit in reused or Taproot related addresses that could migrate to safer formats.
These coins represent the largest share of the exposed supply. According to the report, these addresses can still move funds to newer cryptographic structures.
The paper notes that most Bitcoin remains protected today. Around 65% of the supply is considered secure under current cryptographic conditions.
Developers also continue improving wallet software and address standards to reduce exposure.
Quantum Computing Still Years Away From Breaking Bitcoin Encryption
Bitcoin relies on elliptic curve cryptography to secure private keys. A successful attack would require large scale quantum systems with advanced error correction.
Ark Invest estimates that breaking Bitcoin encryption would require at least 2,330 logical qubits.
The process would also require millions or billions of quantum gates. Current machines operate far below these levels and remain in early development stages.
Most systems today function within the so-called NISQ era with limited logical qubits.
Ark Invest also outlines several stages in quantum computing development. Early stages focus on research and experimental computing tasks.
These systems help industries such as chemistry and materials science.
Later stages could eventually weaken older cryptographic methods. However, the stage required to threaten Bitcoin remains far from current capabilities.
The report states that such systems would likely disrupt internet security before affecting Bitcoin.
Companies including Google, IBM, and Microsoft continue research on quantum systems. Some industry forecasts place the first successful cryptographic break around the mid-2030s.
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Bitcoin Community Explores Quantum Safe Security Options
Researchers say the Bitcoin network must prepare long term security updates.
These updates could include new address formats and stronger digital signature systems. Many experts suggest adopting post quantum cryptography to address future risks.
Post quantum cryptography includes signature schemes such as ML-DSA and SLH-DSA.
These systems rely on mathematical methods designed to resist quantum attacks. Developers consider them possible tools for long term blockchain security.
One proposal under discussion is Bitcoin Improvement Proposal 360. The proposal introduces a Pay to Merkle Root address type that reduces certain Taproot vulnerabilities.
However, the proposal does not yet include post quantum digital signatures.
Chris Tam, president of quantum innovation at BTQ Technologies, commented on the approach.
He said the proposal does not fully solve the long term problem. “The proposal introduces a new address format but does not include post quantum digital signatures,” Tam said.
Researchers note that any large upgrade would require community agreement.
Bitcoin governance relies on consensus among developers, miners, and node operators. Because of this structure, implementing major changes can take time.
