according to a white paper released on Wednesday by Ark Invest and the Bitcoin-focused financial services company Unchained, about 65.4% of the Bitcoin supply is not threatened by breakthroughs in quantum computing, but about 34.6% of the BTC supply still faces risks.
This includes about 5 million bitcoins (accounting for 25% of the total supply) that are considered migratable due to address reuse; another 1.7 million bitcoins (accounting for 8.6% of the total supply) are believed to be lost in P2PK (Pay to Public Key) addresses, which are the earliest form of transaction scripts on the Bitcoin blockchain that lock funds directly to a public key. In addition, due to the address type being P2TR (Pay to Taproot), another 200,000 bitcoins (about 1%) are considered migratable.
The report points out that if quantum computers can break Bitcoin's Elliptic Curve Cryptography (ECC), then this supply would be highly vulnerable to quantum theft. Breaking ECC requires about 2,330 logical qubits and tens of millions to billions of quantum gates.