bitcoin-dev

51% Attack via Difficulty Increase with a Small Quantum Miner

51% Attack via Difficulty Increase with a Small Quantum Miner

Original Postby Antoine Riard

Posted on: March 20, 2024 20:42 UTC

The email from Antoine delves into the potential implications of quantum computing on cryptocurrency mining, specifically focusing on how attacks similar to the classical 51% attacks could be conducted using quantum algorithms like Grover's algorithm.

These attacks would enable malicious actors to double-spend and claim all revenue from block rewards. Grover's algorithm is noted for its efficacy in solving problems with hidden structures, such as those encountered in proof-of-work (PoW) systems used by cryptocurrencies, where solutions can be quickly verified.

However, Antoine raises concerns about the practicality of employing Grover's algorithm for dynamic block template construction and the calculation of corresponding PoWs. The inclusion of last-minute, high-fee transactions in a block template could invalidate prior computations made by the algorithm due to its inability to adapt to rapid changes in the transaction fee market. This limitation is contrasted with classical computers, which do not face the same challenge of being unable to observe computation results until the process concludes. This inflexibility might undermine the feasibility of 51% attacks in environments where block rewards are no longer the primary incentive, hinting at the challenges quantum computing faces in adapting to live, fluctuating markets.

Additionally, the discussion touches on the importance of understanding the qubit format and the solid-state technology used in these quantum computations. Such knowledge is crucial for evaluating the energy costs of quantum mining operations in comparison to traditional ASIC-based mining setups that rely on hydroelectric power. This comparison is vital for assessing the sustainability and economic viability of quantum mining within the existing infrastructure and environmental considerations.