In a joint study titled "Bitcoin and Quantum Computing," released on March 12, 2026, analysts from Ark Invest and Unchained concluded that approximately 35% of Bitcoin's supply could theoretically be threatened by powerful quantum computers of the future, though current technology is far from possessing such capabilities.
The researchers pointed out that despite the theoretical attack surface, the Bitcoin network may have years to adapt before quantum computing poses a practical threat.
Nearly 6.9 Million BTC Could Be Theoretically Exposed
The report estimates that around 6.9 million BTC (approximately 34.6% of the total supply) are held in address types that could become vulnerable if cryptographic-related quantum computers (CRQCs) emerge in the future. These Bitcoins are categorized based on how their cryptographic keys are exposed on-chain.
The largest group consists of reused addresses, where public keys have been exposed in previous transactions. Researchers estimate that about 5 million BTC (around 25% of the supply) fall into this category.
Additionally, approximately 1.7 million BTC (about 8.6%) are held in older Pay-to-Public-Key (P2PK) addresses. In this early Bitcoin address format, public keys are directly visible on the blockchain. This category is estimated to include about 1 million BTC believed to belong to Bitcoin's pseudonymous founder, Satoshi Nakamoto.
The report also highlights that around 200,000 BTC (about 1% of the supply) are associated with Taproot (P2TR) addresses, which could potentially migrate in the future as certain key-path spending mechanisms expose public keys upon spending.
Quantum Hardware Still Far From Breaking Bitcoin
Despite the theoretical vulnerabilities, the report emphasizes that current quantum technology is nowhere near capable of breaking Bitcoin's cryptography. Bitcoin relies on Elliptic Curve Cryptography (ECC) to secure transactions. Researchers estimate that a quantum computer would need approximately 2,330 logical qubits and billions of quantum operations to break this system.
Today's quantum computers are in what researchers call the "Noisy Intermediate-Scale Quantum" (NISQ) era. Current systems typically have around 100 logical qubits, far below the level required to threaten Bitcoin's security.
David Puell, a researcher at Ark Invest, suggests that the development of quantum capabilities may occur incrementally rather than through a sudden breakthrough known as "Q-Day." If quantum computing progresses gradually through visible milestones, developers would have ample time to introduce upgrades to Bitcoin's security framework.
Quantum Breakthroughs Would Affect the Entire Internet
Another key point from the report is that Bitcoin may not be the first system to be significantly impacted by a major quantum breakthrough. The same cryptographic algorithms used by Bitcoin are widely employed across the global internet, banking infrastructure, and digital communication systems.