While it may sound like a concept from a futuristic video game, recent findings indicate that quantum hackers could potentially compromise Bitcoin’s blockchain and pilfer coins during transactions sooner than previously anticipated.
Could Bitcoin Face an Imminent Threat?
A new whitepaper and blog post released on Tuesday by the Quantum AI team at Google indicates that the cryptographic security of Bitcoin and Ethereum could be compromised with less than 500,000 physical qubits and around 1,200 “logical” qubits—much lower than the previously suggested “millions.”
Most cryptocurrencies, including Bitcoin, utilize 256-bit elliptic curve cryptography (ECDLP-256), a robust mathematical mechanism based on the discrete logarithm problem to secure wallets and transactions. The new research reveals a marked decrease in the resources required to breach ECDLP-256. The blog states:
“We believe that these circuits can run on a superconducting qubit CRQC with under 500,000 physical qubits in a matter of minutes, considering standard hardware capabilities that align with some of Google’s leading quantum processors. This represents about a 20-fold reduction in the number of physical qubits needed to solve ECDLP-256, continuing a longstanding trend of optimization in compiling quantum algorithms for fault-tolerant circuits.”
According to the whitepaper, “Cryptographically-relevant quantum computers (CRQS) pose significant risks to the public-key cryptography widely in use.” Rather than focusing solely on stealing from wallets, the research suggests the possibility of a live attack where a quantum adversary could hijack Bitcoin mid-transaction within roughly 9 minutes by rapidly using the temporarily exposed public key to derive the private key, providing a 41% chance of circumventing Bitcoin’s 10-minute block confirmation time. This might render Ethereum somewhat less vulnerable, as it processes transactions more swiftly.
These findings add a new layer of complexity to Taproot, Bitcoin’s upgrade from 2021. While Taproot improved privacy and efficiency, it inadvertently began exposing public keys on-chain by default, eliminating the protective “hash-first” layer that older address formats utilized. Consequently, around 6.9 million BTC, including coins from the Satoshi era and those with high address reuse, are now more susceptible to quantum threats.
A quantum computer operates on the principles of quantum mechanics, allowing it to process information in unique ways that traditional computers cannot. Unlike classical bits, which can be either a 0 or a 1, qubits can represent both values simultaneously, enabling the machine to evaluate multiple possibilities at once. This capability means that for certain mathematical challenges (such as factoring large numbers crucial for encryption), a powerful quantum computer could resolve issues in minutes that would take a classical supercomputer longer than the age of the universe.
What This Means for Anxious Traders
While it’s true that no such quantum machine exists yet, Google has set an internal target of 2029 for transitioning to post-quantum security, shortening the timeline for “Q-day.” Experts caution that migrating to post-quantum cryptography will be a lengthy process, even if the hardware is still in development.
On the social network X, several users have already voiced their concerns regarding quantum risks. Nic Carter, co-founder of Coin Metrics and a Bitcoin proponent, shared another study released today from Oratomic, Caltech, and UC Berkeley, which indicates that quantum computers could break crypto security using merely 10,000 reconfigurable atomic qubits.
“The most astonishing thing is that the Google Quantum AI paper (above) may not even be the most alarming quantum research published _today_.”https://t.co/mSZi5Lk7do
Approximately one-third of Bitcoin’s total supply is now categorized as potentially vulnerable to quantum threats over the long term, which could affect how traders assess older coins, Taproot implementation rates, and address reuse practices. Traders should keep an eye on Taproot adoption metrics, the status of upgrades like BIP-360, and whether Bitcoin developers implement an updated migration strategy as Google’s 2029 deadline approaches.
Cover image from Perplexity, BTCUSD chart from Tradingview