Resource Needs for Critical Operation in Potential Quantum Attack Dropped by 86%: Why Now?
The estimated resource score for the critical operation required for a potential quantum attack on Bitcoin and Ethereum has been reduced by approximately 86% in about two months.
A technical study prepared by Theta Labs CTO Jieyi Long and researchers from various crypto projects and academic institutions reduced the resource score of a circuit designed for this critical operation from 10.75 billion points to 1.496 billion points. Although this result is less than half the level previously announced by Google, it was noted that the two studies used different calculation methods.
Researchers calculated the cost in question by combining the number of logical qubits required by the circuit with the number of Toffoli gates, which constitute a significant part of the processing time. The circuit prepared at the end of the open competition, which lasted about two months, required 1,151 logical qubits and 1.30 million Toffoli gates.
Resource costs dropped rapidly in quantum research
More than 100 people, including researchers associated with the Ethereum Foundation, Eigen Labs, StarkWare, Starknet Foundation, Theta Labs, Brevis, Sei Labs, and Trail of Bits, contributed to the competition. Researchers announced that progress continued even after the paper’s submission deadline. One of the subsequent designs reduced the number of Toffoli gates to 952,707, while another reduced the logical qubit requirement to 813.
Google Quantum AI announced a 2029 target in March for transitioning to quantum-resistant cryptography. However, the company did not publish the details of its own circuit. The comparison between the new study and Google’s measurement was presented only as a numerical reference due to different interfaces and accounting rules.
The circuit presented in the study is not an actual attack. Researchers did not account for physical error correction and did not provide a full implementation of Shor’s algorithm.
Quantum security preparations continue for Bitcoin and Ethereum
The development has reignited the discussion on why preparations for cryptographic transition must begin years in advance, even though the quantum threat has not yet materialized. Coinbase’s Quantum Computing and Blockchain Independent Advisory Board estimates that approximately 7 million BTC are held in public-key addresses that could be exposed to quantum attacks in the future. The board also emphasized that no quantum computer capable of performing such an attack exists today.
Ethereum, on the other hand, targets December 2029 to achieve full security against quantum attacks in its execution, consensus, and data layers. Long stated that the issue must be addressed now because solutions cannot be applied retroactively and preparations can take years.