How long until Bitcoin is broken by quantum computers? Google reveals the hacking threshold has dropped 20-fold; experts worry a governance crisis could become a fatal flaw

The quantum crisis of Bitcoin is no longer science fiction! Google Quantum AI’s latest white paper states that the threshold for breaking Bitcoin has been significantly lowered to 1,200 logical qubits, and quantum hardware is expected to meet the requirements before 2033. Experts warn that the real crisis is not physics, but Bitcoin’s community being extremely conservative about its “governance mechanism.” To upgrade to post-quantum cryptography, network throughput may be cut in half and transaction fees could surge by two times. This consensus battle—one that could determine Bitcoin’s survival—may require a prolonged tug-of-war lasting up to 10 years. The million Bitcoins mined by Satoshi Nakamoto in the early days may become the first wave of “sacrificial lambs” to be looted.
(Background: AmericanFortress’s “Quantum-Resistant Bitcoin” calls for a soft fork to freeze Satoshi’s 1.1 million Bitcoins, helping keep them from the threat of quantum attacks.)
(Background: The Trump administration pours $2 billion into “quantum computing”! Investing in IBM and other 8 major companies—concept stocks surged as much as 25% pre-market.)

Table of Contents

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• “Harvest First, Decrypt Later”: The Threat Has Already Lurked
• Painful Upgrade Costs: Throughput Cut in Half, Fees Jump by Two Times
• Physics Isn’t the Problem—The Hardest Part Is “Community Governance”

How far away is the day Bitcoin is compromised? The answer may be closer than most people think.

According to an epoch-making white paper released by Google Quantum AI in March 2026, by optimizing the Shor algorithm, cracking the 256-bit elliptic curve cryptography (ECDSA) that protects every Bitcoin address requires no more than 1,200 logical qubits (Logical qubits) and fewer than 500,000 physical qubits. This number is 20 times lower than the industry’s broadly accepted estimates from five years ago.

Compared with the quantum development roadmaps of major tech giants: IonQ aims to reach 1,600 logical qubits by 2028; IBM expects to launch the Blue Jay system with 2,000 logical qubits by 2033. This means Bitcoin’s “quantum countdown timer” could be zeroed out no later than 2033.

“Harvest First, Decrypt Later”: The Threat Has Already Lurked

This crisis is divided into three levels. First, national-level intelligence agencies may have already been carrying out a “Harvest Now, Decrypt Later (HNDL)” strategy. Any private transactions on the blockchain or cross-chain messages—once intercepted and stored—can be easily decrypted in the future when quantum computers mature.

Second, the most deadly blow will be targeted precisely at old addresses that expose public keys. The most dangerous targets are none other than Satoshi Nakamoto (Satoshi Nakamoto) and the more than one million Bitcoins he mined in the early days—worth a fortune. These early P2PK-format addresses have their public keys openly displayed on the blockchain for 17 years. Once cryptographically meaningful quantum computers emerge, these massive unmovable funds—money that nobody can transfer—will become the hackers’ first and top target for looting.

Even more chilling is the “instant replacement attack.” When you initiate a transaction on some day in the future and, during the 10-minute waiting period before block confirmation, a powerful quantum computer could derive the private key from the public key you broadcast and steal the funds before the transaction is settled.

Painful Upgrade Costs: Throughput Cut in Half, Fees Jump by Two Times

In response to quantum threats, technical solutions already exist. The NIST (National Institute of Standards and Technology) finalized the post-quantum cryptography (PQC) standards as early as 2024. However, the real bottleneck lies in this: whether the Bitcoin network is willing to pay the high cost to upgrade.

Research shows that the amount of data required for post-quantum signatures is hundreds of times greater than it is today. If there is a full transition to the new standard, Bitcoin’s network throughput will drop by 52% to 57%, and transaction fees will surge by 2 to 3 times. This is a “defensive downgrade”: users must immediately bear the high costs in exchange for preventing a threat that has not yet materialized in practice.

Physics Isn’t the Problem—The Hardest Part Is “Community Governance”

Looking back at history, the SegWit upgrade—then capable of delivering real performance improvements—triggered a split and even an internal “civil war” within the Bitcoin community lasting for two years. Today, pushing a quantum-resistant upgrade in this community—one that is extremely resistant to centralized coordination and extremely conservative—(such as the currently proposed BIP 360 and BIP 361) is estimated to require up to 10 to 15 years to reach consensus—exactly overlapping with the countdown time when the quantum threat arrives.

By contrast, Ethereum (Ethereum) founder Vitalik Buterin has already personally promoted a multi-layer quantum contingency roadmap, even allowing accounts to independently switch to quantum-resistant signatures.

Experts warn that Bitcoin will not instantly go to zero, but its path to survival will become extremely narrow. This race is no longer a showdown between quantum computing and cryptography—it’s whether the speed of quantum hardware development can be outpaced by the Bitcoin community’s “governance capability,” i.e., its ability to make difficult collective decisions under pressure.