Google Warns: Is the End of Bitcoin Approaching? Quantum Computers Could Threaten Crypto Sooner Than Expected

Recent research suggests that quantum computers could potentially undermine Bitcoin’s blockchain security and facilitate the theft of coins mid-transaction sooner than previously anticipated.

Key Takeaways

Google’s Quantum AI team published research indicating that Bitcoin and Ethereum’s security could be compromised by quantum computers sooner than expected.
Cryptography used in these networks may be broken with fewer resources than previously thought, with the possibility of attacks happening mid-transaction.
Taproot’s update, while improving privacy, has also made many Bitcoin addresses more vulnerable to quantum threats.
The migration to post-quantum cryptography is urgent, especially given the timeline set by Google for 2029.
The cryptocurrency community is increasingly concerned about potential quantum attacks, which could affect how Bitcoin is valued and utilized.

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Are We Facing a Bitcoin Apocalypse?

A whitepaper and blog post released on Tuesday by Google’s Quantum AI team indicate that the cryptographic methods used in Bitcoin and Ethereum could be compromised with less than 500,000 physical qubits and approximately 1,200 logical qubits, which is significantly lower than the “millions” previously anticipated.

Most cryptocurrencies, including Bitcoin, safeguard wallets and transactions using 256-bit elliptic curve cryptography (ECC), a robust mathematical system based on the discrete logarithm problem (ECDLP-256). The study points out a striking reduction in the resources required to compromise ECDLP-256. The blog states:

"We estimate that these circuits can be executed on a superconducting qubit CRQC with fewer than 500,000 physical qubits in a few minutes, given standard assumptions about hardware capabilities that are consistent with some of Google’s flagship quantum processors. This represents a roughly 20-fold decrease in the number of physical qubits necessary to resolve ECDLP-256 and continues a long history of improving quantum algorithm compilation into fault-tolerant circuits."

The whitepaper warns, "Cryptographically-relevant quantum computers (CRQS) pose a threat to widely deployed public-key cryptography." Rather than targeting wallets, the research investigates a live attack scenario where a quantum attacker could potentially steal Bitcoin mid-transaction in around 9 minutes by quickly deriving the private key from a temporarily exposed public key. This presents a 41% chance of bypassing Bitcoin’s 10-minute block confirmation time. Interestingly, Ethereum may be slightly less exposed since it confirms transactions more rapidly.

This development prompts a re-evaluation of Taproot, Bitcoin's upgrade from 2021. While Taproot improved privacy and efficiency, it also began exposing public keys on the blockchain by default, thereby removing the “hash-first” protective layer that older address formats provided. Consequently, this has increased the number of quantum-exposed bitcoins to about 6.9 million, including coins from the early days and heavily used addresses.

A quantum computer utilizes the principles of quantum physics to process data in ways that traditional computers cannot. Instead of relying on bits that represent either 0 or 1, quantum computers use qubits, which can represent 0, 1, or both simultaneously, allowing these machines to investigate multiple possibilities concurrently. While classical computers assess options sequentially, a powerful quantum computer can resolve certain mathematical challenges (like the factorization of large numbers used in cryptography) in minutes, tasks that would take classical supercomputers longer than the lifespan of the universe.

Although no operational quantum computer exists yet, Google has set an internal target of 2029 for transitioning to post-quantum cryptography, which shortens the timeline for what some refer to as “Q-day.” Experts caution that this migration will require years, even if the necessary hardware isn’t currently available.

Recently, discussions on the social platform X have reflected growing anxiety about quantum threats. Nic Carter, co-founder of Coin Metrics and a Bitcoin advocate, highlighted another research paper from Oratomic, Caltech, and UC Berkeley, suggesting that quantum computers might break cryptography with as few as 10,000 reconfigurable atomic qubits.

"And the craziest thing is that the Google Quantum AI paper (above) is maybe not even the most concerning quantum paper released today," — Nic Carter (@nic_carter) March 31, 2026.

Currently, about one-third of Bitcoin's total supply is seen as potentially exposed to quantum risks over the long term. This alarming reality could reshape how traders assess older coins, Taproot adoption, and address reuse practices. Investors should monitor metrics surrounding Taproot adoption, developments regarding BIP-360-style upgrades, and whether Bitcoin developers adapt their migration strategies as Google’s 2029 deadline approaches.

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Cover image from Perplexity, BTCUSD chart from Tradingview.