Today, a new Bitcoin Improvement Proposal (BIP) was introduced, outlining a clear plan to migrate Bitcoin to post-quantum (PQ) cryptography, with consequences for wallets, miners, exchanges, and holders who fail to upgrade.

The proposal introduces a phased plan to eliminate reliance on current ECDSA/Schnorr signatures, which may be vulnerable to future quantum computer attacks that could break private keys to steal bitcoin. The plan turns quantum security into a hard incentive, “fail to upgrade and you will certainly lose access to your funds.”

“We seek to secure the value of the UTXO set and minimize incentives for quantum attacks,” the proposal stated. “Never before has Bitcoin faced an existential threat to its cryptographic primitives. A successful quantum attack on Bitcoin would result in significant economic disruption and damage across the entire ecosystem. Beyond its impact on price, the ability of miners to provide network security may be significantly impacted.”

The proposal outlines three phases:

• Phase A would prohibit sending bitcoin to quantum-vulnerable addresses, encouraging the adoption of the post-quantum address type (P2QRH). 
• Phase B, expected to activate two years after phase A, would make all ECDSA/Schnorr based transactions invalid, effectively freezing any funds that haven’t been migrated. 
• Phase C, which remains optional and subject to further research, may offer a recovery path with a proof of possession of a corresponding BIP-39 seed phrase.

The motivation behind the proposal is the accelerating progress in quantum computing. In 2024, NIST approved several post-quantum signature schemes, while some experts estimate that a quantum computer capable of breaking classical encryption could arrive as early as 2027-2030. The proposal warns that roughly 25% of all bitcoin have exposed public keys on-chain, making them vulnerable to quantum theft.

By blocking new transactions to quantum-vulnerable addresses, the proposal aims to reduce the future attack surface with each new UTXO created. This change is designed to speed up the adoption of post-quantum address formats by making them the only valid option going forward. Given how long Bitcoin upgrades take to fully implement, this approach aims to push stakeholders to act sooner.

Those interested can read more about the BIP here.