{"id":907396,"date":"2026-05-21T12:22:20","date_gmt":"2026-05-21T17:22:20","guid":{"rendered":"https:\/\/newsycanuse.com\/index.php\/2026\/05\/21\/9-minutes-to-crack-a-bitcoin-wallet-how-real-is-the-quantum-threat\/"},"modified":"2026-05-21T12:22:20","modified_gmt":"2026-05-21T17:22:20","slug":"9-minutes-to-crack-a-bitcoin-wallet-how-real-is-the-quantum-threat","status":"publish","type":"post","link":"https:\/\/newsycanuse.com\/index.php\/2026\/05\/21\/9-minutes-to-crack-a-bitcoin-wallet-how-real-is-the-quantum-threat\/","title":{"rendered":"9 Minutes to Crack a Bitcoin Wallet: How Real Is the Quantum Threat?"},"content":{"rendered":"

Bitcoins <\/p>\n

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On March 30, 2026, Google Quantum AI published a <\/span>new whitepaper<\/span><\/a> revealing that a theoretical quantum computer could derive a private key from a public key on the Bitcoin<\/a> network in just a few minutes. This timeframe closely aligns with Bitcoin\u2019s 10-minute mining cycle, raising the scenario of an \u201cOn-Spend Attack\u201d where a transaction pending confirmation could be intercepted and replaced.<\/span><\/p>\n

Additionally, Google experts recommended that blockchain projects complete their migration to Post-Quantum Cryptography (PQC) before 2029 to safeguard digital signatures and transactions against sufficiently powerful future quantum computers.<\/span><\/p>\n

Bitcoins <\/span>Understanding the Quantum Threat<\/b>\u00a0<\/span><\/span><\/h2>\n

The research illustrates a scenario in which quantum computers could compromise the core security mechanisms of Bitcoin and Ethereum. Instead of a direct attack on the wallet, this method targets the public key\u2014which becomes visible on the blockchain during a transaction\u2014to derive the private key, the ultimate factor controlling the assets.<\/span><\/p>\n

Current security relies on cryptographic problems considered nearly impossible for classical computers to solve, but which could be significantly accelerated by quantum systems. According to Google\u2019s estimates, a theoretical quantum system could perform this calculation using approximately <\/span>1,200\u20131,450 logical qubits<\/b> and <\/span>70\u201390 million Toffoli<\/b> gates, with a total physical qubit count under <\/span>500,000 physical<\/b>\u2014substantially lower than previous projections. These estimates were validated using the Zero-Knowledge Proof (ZKP) method.<\/span><\/p>\n

In architectures utilizing superconducting systems, execution time could be reduced to mere minutes. This is particularly critical because public keys are typically exposed only during the transaction process, creating a narrow window of vulnerability where assets could be exploited if the private key is derived rapidly enough.<\/span><\/p>\n

However, the research emphasizes that quantum computers with sufficient power to execute this scenario do not yet exist, and current estimates reflect capabilities under theoretical conditions.<\/span><\/p>\n

Bitcoins <\/span>Inside Bitcoin\u2019s 10-Minute Window<\/b>\u00a0<\/span><\/span><\/h2>\n

A primary scenario highlighted in the report is the \u201c<\/span>On-Spend Attack<\/b>,\u201d targeting transactions pending in the network\u2019s mempool. Once a public key is broadcast after a transaction is initiated, a theoretical quantum system could attempt to derive the private key before the next block is confirmed.<\/span><\/p>\n

With the Bitcoin network\u2019s average confirmation time of 10 minutes, a \u201cwaiting window\u201d is created, allowing an attacker to compete directly with the original transaction. If the calculation is completed in time, they could broadcast a replacement transaction with a higher fee to ensure priority inclusion in the block.<\/span><\/p>\n

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\"bitcoins<\/p>\n

Race Against the Block: Attack Speed vs. Network Variance. Source: Google<\/p>\n<\/div>\n

Consequently, the success of such an intervention is strictly tied to the duration of this window. Blockchains with shorter block times, such as Litecoin (approx. 2.5 minutes), Zcash (75 seconds), or Dogecoin (1 minute), significantly narrow the operational timeframe for an attacker.<\/span><\/p>\n

However, these estimates assume a non-congested network. In practice, an attacker could intentionally spike fees or flood the mempool to increase the probability of their fraudulent transaction being prioritized for confirmation.<\/span><\/p>\n

Bitcoins <\/span>The Hardware Gap \u2014 and the Race to PQC<\/b>\u00a0<\/span><\/span><\/h2>\n

While estimates show a significant reduction in attack execution time, a cryptanalytically relevant quantum computer (CRQC) does not yet exist. Only specific quantum architectures, such as superconducting systems, can potentially reach the speeds required for fast-attack scenarios, while other systems remain limited by processing constraints.<\/span><\/p>\n

In a March 25, 2026 <\/span>announcement<\/span><\/a>, Heather Adkins, VP of Security Engineering at Google, and Sophie Schmieg, Senior Staff Cryptography Engineer, stated that the company aims to complete its transition to <\/span>Post-Quantum Cryptography (PQC)<\/b> by 2029. This move is designed to protect encryption and digital signatures from future quantum-enabled adversaries.<\/span><\/p>\n

This transition is vital for authentication systems and digital signatures\u2014the backbone of blockchain transactions. During this period, short-term mitigations include restricting address reuse and minimizing public key exposure.<\/span><\/p>\n

Bitcoins <\/span>Not All Risks Are Equal<\/b><\/span><\/h2>\n

<\/span>Wallet Exposure<\/b>\u00a0<\/span><\/span><\/h3>\n

The actual impact of the quantum threat varies across different wallet types, depending on whether the public key has been previously exposed on the blockchain.<\/span><\/p>\n