Researchers Halve Quantum Resource Benchmark for Potential Bitcoin, Ethereum Attacks
Quantum Attack Cost Reduced Significantly in New Research
A team of researchers has substantially lowered the estimated resource cost for a key operation in potential quantum attacks on Bitcoin and Ethereum. Their new benchmark score is 86% lower than initial figures, achieved through a public challenge over two months.
Key Findings from the Study
- The circuit requires 1,151 logical qubits, which act as quantum memory, and 1.30 million Toffoli gates, which are basic operations.
- The combined score was reduced from 10.75 billion to 1.496 billion, which is less than half of Google's previously reported benchmark.
- More than 100 contributors from organizations such as the Ethereum Foundation, Eigen Labs, StarkWare, and Theta Labs participated.
Details from the Research Paper
The paper, authored by Theta Labs CTO Jieyi Long and others, describes the circuit design and improvements. The researchers emphasize that this is not an attack; it does not account for physical error correction or include a full implementation of Shor's algorithm, a theoretical method for breaking current encryption.
Broader Context and Related Developments
Google Quantum AI published its own estimates in March 2026, setting a 2029 target for migration to post-quantum cryptography, but did not release its circuit. The comparison between the new benchmark and Google's is numerical context, as different accounting methods were used. Additionally, a June 2026 report from Coinbase estimated that about 7 million BTC are in addresses exposed to quantum attacks due to visible public keys, though no quantum computer can currently break blockchain cryptography. Ethereum is targeting full quantum resistance across its layers by December 2029.
Confirmed Facts
The resource benchmark score was reduced by 86% to 1.496 billion through a public challenge. The circuit's specifications are 1,151 logical qubits and 1.30 million Toffoli gates. Researchers continued to submit improvements after the paper's cutoff, with some achieving lower numbers like 952,707 Toffoli gates and 813 logical qubits.
Unresolved Comparisons
The researchers note that Google used different interfaces and accounting conventions, so the comparison is presented as numerical context rather than a formal claim of outperformance. The full implications for real-world quantum threats remain uncertain.
Implications for Blockchain Security
This research highlights the progressing threat of quantum computing to cryptographic systems used by Bitcoin and Ethereum. Theta Labs' Jieyi Long stated, "It is urgent because the remedy takes years and cannot be applied retroactively." StarkWare's Eli Ben-Sasson said that cutting the cost in half means timelines for quantum attacks should be reassessed.
Future Preparedness Efforts
Ethereum developers are working towards full post-quantum security by 2029. Bitcoin developers are also preparing, though specific timelines are not detailed in the source. The ongoing research suggests that quantum threats are a long-term concern requiring proactive measures.
