Bitcoin Faces Theoretical Quantum Threat, Ark Invest Reports

A report from Ark Invest and Unchained reveals 35% of Bitcoin supply could be at risk from future quantum computers, though current tech remains years away.

According to a new analysis by Ark Invest and Unchained, the threat to the network remains largely theoretical at this stage, as modern quantum technology is far from being able to compromise the network’s cryptographic defenses.

In a joint report titled “Bitcoin and Quantum Computing,” published on March 12, 2026, researchers estimate that approximately 35% of the total Bitcoin supply could theoretically be exposed to risk if a sufficiently powerful quantum computer is developed in the future.

However, analysts emphasize that such a technological breakthrough is likely years or even decades away.

Up to 6.9 Million BTC Theoretically Exposed

According to the study’s estimates, around 6.9 million BTC, or approximately 34.6% of the total supply, resides in addresses that could become vulnerable if a so-called Cryptographically Relevant Quantum Computer (CRQC) is created.

The largest portion of this potential exposure comes from reused addresses, where the public key has already been revealed in previous transactions. Experts estimate that about 5 million BTC, or roughly 25% of the total supply, falls into this specific category.

Another 1.7 million BTC—approximately 8.6% of the supply—is held in the older Pay-to-Public-Key (P2PK) address type. In this format, the public key is directly visible on the blockchain. This category includes approximately 1 million BTC believed by analysts to belong to Bitcoin’s creator, Satoshi Nakamoto.

The report also identifies around 200,000 BTC associated with newer Taproot (P2TR) addresses, which in certain scenarios could reveal public keys when funds are spent.

Quantum Technology Remains Far from a Real Threat

Despite the theoretical vulnerability, researchers stress that current quantum technology is significantly weaker than what is required to compromise Bitcoin’s cryptography.

The network utilizes Elliptic Curve Cryptography (ECC) to secure transactions. To break this system using a quantum computer, researchers estimate that approximately 2,330 logical qubits and billions of quantum operations would be needed.

Current quantum computers, however, are in a stage known as Noisy Intermediate-Scale Quantum (NISQ). Most possess only about 100 logical qubits, placing them well below the threshold necessary for such an attack.

According to Ark Invest analyst David Puell, the development of quantum technology will likely occur gradually rather than through a sudden technological breakthrough often referred to as “Q-Day.”

This suggests that if quantum computing begins to advance toward a critical level, Bitcoin developers will likely have enough time to implement new defensive mechanisms.

Potential Quantum Breakthrough Would Affect the Entire Internet

The report also notes that BTC would likely not be the first system affected by powerful quantum computers.

The same cryptographic algorithms used in BTC are widely deployed across global internet infrastructure, banking systems, and secure communications. A quantum computer capable of breaking Bitcoin signatures would likely compromise a range of other critical digital systems as well.

Such a scenario would trigger a global transition to post-quantum cryptography involving governments, banks, and technology companies.

Post-Quantum Security Solutions Under Development

According to the research, the Bitcoin ecosystem is already beginning to explore possible solutions for future quantum risks.

One potential strategy is the introduction of quantum-resistant address formats via a soft fork, which would allow users to gradually migrate their funds to new cryptographic algorithms such as ML-DSA or SLH-DSA.

The report mentions a proposal known as BIP-360, or Pay-to-Merkle-Root (P2MR), which aims to limit certain transaction mechanisms that reveal public keys on the blockchain.

Over time, developers could encourage users to move their funds to new address formats that remain secure even against future generations of quantum computers.

Analysts believe such a gradual adaptation could allow the Bitcoin network to evolve alongside technological progress without facing a sudden security collapse.