Bitcoin and Quantum Computing

The discussion begins with an acknowledgment of the insightful report presented, specifically appreciating the analysis on the potential threats to Proof of Work (PoW) systems by quantum computing advancements. It is pointed out that while the report convincingly argues that breaking the Elliptic Curve Discrete Logarithm Problem (ECDLP) might precede any quantum threat to PoW, the transition from solving ECDLP to compromising PoW might be less challenging than initially surmised. This revelation holds significant implications for Bitcoin, suggesting that the concept of Bitcoin itself faces existential threats from quantum computing progress, beyond just the immediate concerns of today’s network security.

Further scrutiny of the report reveals a few areas needing correction or clarification. A discrepancy is highlighted in the resource usage table on page 18, where two schemes are mistakenly listed under the same name and date, indicating a possible oversight in the differentiation of these schemes. Additionally, a potential typographical error is identified in the discussion on page 30, which mentions "mid January 2015" in the context of BTC behind revealed public keys. The correct reference likely being "mid January 2025", prompts a revision suggestion to ensure the accuracy of future projections and historical data comparisons.

On page 35, the report touches upon the strategy of privately submitting transactions vulnerable to Cryptographically Relevant Quantum Computing (CRQC) attacks to trusted miners. This section, however, is critiqued for not fully addressing the risks associated with such an approach. Specifically, it overlooks the possibility of an attacker orchestrating a reorganization of the last blocks (reorg) to illicitly acquire funds. This scenario becomes particularly concerning for large Unspent Transaction Outputs (UTxOs) in the era post the 2032 halving, underscoring the need for a more comprehensive risk assessment regarding the reliance on trusted miners in the face of evolving quantum threats.