03.04.2026 23:40

**Quantum Computing AdvancesThreaten Bitcoin’s Encryption Within Minutes**

Google’s quantum‑computing researchers published a paper on March 30 that has sent shockwaves through the cryptocurrency community. Their analysis shows that a quantum machine equipped with roughly 500,000 physical qubits—far fewer than earlier estimates—could theoretically undo the elliptic‑curve cryptography (ECDLP‑256) that safeguards Bitcoin wallets. This revision dramatically compresses the timeline for when the quantum risk might materialise.

**How a Quantum Attack Could Exploit a Live Transaction**
The invasion of privacy lies in the brief moment a Bitcoin transaction is broadcast before it is confirmed. During those ten minutes the sender’s public key is exposed, creating a narrow window of vulnerability. According to the Google team, a quantum adversary who has pre‑computed the necessary quantum circuits could capture that window with about a 41 % probability of success in under nine minutes. It is not a certainty, but the odds are far higher than the negligible risk previously imagined.

**Who Faces the Greatest Exposure** About 6.9 million Bitcoin—roughly 1.7 million of which belong to the “Satoshi” era—are considered at heightened risk from longer, more deliberate quantum attacks. Older wallets that reuse addresses or disclose their public keys are especially exposed because they require no fleeting window; a quantum computer merely needs sufficient qubits and processing time. Ironically, Bitcoin’s Taproot upgrade, rolled out in 2021 to enhance privacy, unintentionally widened the pool of vulnerable addresses by making public keys more readily visible in certain transaction types.

**Ethereum’s Different Landscape** Ethereum presents a less urgent exposure profile. Its blocks are confirmed far more quickly, shrinking the transaction‑exposure window to mere seconds. Consequently, the nine‑minute quantum attack scenario is far less relevant for the Ethereum network.

**Current State of the Threat** Despite these alarming numbers, the danger remains theoretical for the foreseeable future. No existing quantum hardware approaches the 500,000‑qubit threshold, let alone one capable of error‑corrected Shor’s algorithm execution. Google’s most advanced chip, Willow, operates at a scale far below what the research predicts as essential.

Google has been preparing for this eventuality since 2016, aiming to transition to post‑quantum cryptography (PQC) by 2029. The recent study was conducted using zero‑knowledge techniques to avoid publishing a concrete attack blueprint that could be misused. The Bitcoin community has long been aware of quantum vulnerabilities, and several post‑quantum signature schemes have already been proposed to replace the current ECDSA standard. What Google’s paper does is sharpen the focus: the required qubit count is lower than anticipated, the timeline may be tighter, and the Taproot side‑effect is now documented.

**The Verdict**
Whether the blockchain ecosystem can pivot quickly enough to protect its foundations before a capable quantum computer appears remains an open and unsettling question. The answer, for now, is uncertain.