Bitcoin developers proposing quantum upgrade warn 25% of total BTC supply exposed to attack risk

A group of experienced Bitcoin developers has outlined a new proposal to prepare the network for the inevitable threat of quantum computing.

The initiative, led by Jameson Lopp, Christian Papathanasiou, Ian Smith, Steve Vaile, and Pierre-Luc Dallaire-Demers, focuses on safeguarding vulnerable Bitcoin held in older address types that may be compromised by future quantum breakthroughs.

25% of Bitcoin faces quantum computing risk

The proposal noted that around 25% of all Bitcoin eventually could be at risk if a cryptographically capable quantum computer emerges.

According to the developers, these assets are held in addresses that have already exposed their public keys, making them potential targets for these sophisticated computing machines.

Due to this, the developers stressed that this is not a hypothetical issue for the distant future but a serious risk that requires proactive mitigation.

They warned that a successful quantum attack wouldn’t just impact market value; it could severely undermine trust in the network’s ability to function securely. They stressed:

“An attack on Bitcoin may not be economically motivated – an attacker may be politically or maliciously motivated and may attempt to destroy value and trust in Bitcoin rather than extract value. There is no way to know in advance how, when, or why an attack may occur. A defensive position must be taken well in advance of any attack.”

Three-phase strategy for a quantum-safe transition

To prepare for this threat, the team has laid out a three-phase plan to gradually migrate users from quantum-vulnerable addresses to post-quantum secure alternatives.

The first phase would allow Bitcoin to be sent only to new address types called P2QRH, thereby nudging the network toward quantum resilience. This transition is expected to begin three years after the implementation of BIP-360.

The second phase would invalidate all spends from legacy cryptographic signatures, effectively freezing unupdated addresses after a predetermined block height. According to the developers, this could be roughly five years after phase one begins.

The third and final phase would provide a method for users who missed the migration window to recover their legacy funds using zero-knowledge proofs tied to their seed phrases. However, this step is still under research and would be optional.

Community reaction

Jacob Youngman, a Bitcoin commentator, expressed concern that the changes might lead to the confiscation of inactive or legacy-held coins, possibly including those linked to Satoshi Nakamoto.

According to him:

“The best we can do would be to give users an opt-in solution that protects them from quantum computers.”

However, Lopp addressed the criticism, stating that inactive wallets are just as likely to be exploited by malicious quantum actors if no action is taken.