Google paper outlines how quantum machines could one day crack crypto security

A new research paper from Google Quantum AI has drawn attention for outlining how future quantum computers could, in theory, break the cryptographic systems used by Bitcoin, Ethereum, and other cryptocurrencies within minutes.

The study, titled “Securing Elliptic Curve Cryptocurrencies against Quantum Vulnerabilities: Resource Estimates and Mitigations,” was published on March 30, 2026, by researchers at Google Quantum AI. A Seattle-based technology expert who shared the development with ProPakistani said much of the wider discussion around the findings has remained limited because the results highlight how vulnerable encrypted blockchain systems could become as quantum technology advances.

The paper focuses on how cryptographically relevant quantum computers could exploit weaknesses in the mathematical foundations that secure blockchain wallets and transactions.

Using updated resource estimates, the researchers found that Shor’s algorithm could theoretically solve the 256-bit elliptic curve discrete logarithm problem used in secp256k1, the same cryptographic system that underpins Bitcoin and Ethereum, with roughly 1,200 logical qubits. Earlier assumptions had suggested that millions of qubits might be necessary.

Under certain low-error superconducting quantum architectures, the researchers estimated that such an attack might require fewer than 500,000 physical qubits. That level has not yet been reached, but it is now being viewed as technically plausible rather than purely hypothetical.

One of the paper’s most significant findings involves a possible “on-spend” quantum attack. When a Bitcoin transaction is broadcast to the network, its public key can become temporarily visible in the mempool before the transaction is confirmed. According to the study, a sufficiently advanced quantum computer could theoretically derive the private key from that exposed public key within minutes, potentially allowing an attacker to redirect funds before the transaction is finalized.

The team said it validated its conclusions using zero-knowledge proofs, but intentionally withheld operational attack details out of concern that publishing them could encourage misuse.

Despite the seriousness of the findings, the researchers noted that cryptocurrencies are not currently at immediate risk. The most advanced quantum computers today still operate with only thousands of physical qubits, far below the hundreds of thousands needed to carry out such an attack. For now, the paper serves more as a warning about future risk than a sign of present-day vulnerability, though that future may be closer than many expect.

The study also warns that quantum computing could eventually create broader systemic risks across blockchain ecosystems, especially in areas such as exposed public keys in transactions, smart contracts, proof-of-stake consensus systems, and dormant or abandoned crypto wallets.

Researchers are urging cryptocurrency developers and blockchain communities to start preparing for that future by moving toward post-quantum cryptography standards designed to resist quantum attacks.

Although no cryptocurrency has been hacked through quantum computing so far, the paper offers one of the clearest scientific frameworks yet for understanding how blockchain encryption could eventually be broken. The question is no longer whether it is mathematically possible, but how quickly the engineering catches up. Many analysts on X believe the turning point could arrive around 2030.