Quantum Recovery Of Hashed Address Secured Coins With No Confiscatory Risk

In the discussion surrounding the security of Bitcoin in a post-quantum scenario, there are significant points made about the limitations and applications of various cryptographic recovery methods. A primary concern is raised about the use of P2PK addresses stored by Bitcoin Core's old JBOK wallet system. It is highlighted that these addresses, which reveal public keys on-chain, are not covered by new proposals aiming to enhance security against quantum threats. These proposals focus on hashed address types, explicitly excluding P2PK and P2TR from their scope due to the nature of their public key exposure.

The debate extends into the effectiveness of using zero-knowledge proofs (ZKP) combined with commit-reveal mechanisms as a strategy to protect UTXOs in hashed address types. This approach, although critiqued for potentially including redundant components, is defended for its ability to provide comprehensive coverage across feasible key generation schemes without the need for stateful proofs. However, another perspective is introduced suggesting that internal keys used in P2TR addresses could serve as knowledge asymmetries (KAs), offering a form of protection by using preimages unknown to quantum attackers. This method, however, would represent a separate recovery mechanism and does not align with the proposed combination of ZKP and commit/reveal strategies focused exclusively on hashed addresses.

Further considerations are discussed regarding the vulnerability of any UTXO on a hashed address that might lack a KA, such as those associated with paper wallets or addresses that have been reused. The exposure of an EC public key on the blockchain, whether the address was generated through BIP32 or not, undermines the security provided by HD recovery proofs. This points to a broader necessity for improved practices and hygiene in managing public key data to effectively prepare for quantum threats. The conversation underscores the importance of adapting user behavior and existing security frameworks to mitigate risks associated with quantum computing advancements, particularly emphasizing that these efforts must go beyond merely applying new cryptographic techniques.