Google's Quantum AI team recently warned about risks to Bitcoin and Ethereum from future quantum computers. In a paper released at the end of March 2026, they explained how these machines could break the main security system protecting crypto wallets and transactions.
What is the issue?
Bitcoin and Ethereum rely on elliptic curve cryptography for signing transactions. This math makes it nearly impossible today to guess a private key from a public one. But Shor's algorithm on a powerful quantum computer could solve this problem quickly. The team created smarter versions of the algorithm that needed far fewer resources than earlier guesses—under 1,500 logical qubits and execution in just minutes on realistic hardware. This is about 20 times better than old estimates.
For Bitcoin, around 6.9 million BTC have exposed public keys. This includes old coins that could be stolen once quantum computers arrive. Ethereum faces even broader risks in wallets, smart contracts, staking, and more, putting over $100 billion at potential risk.
Why does it matter?
Blockchains openly share public keys with every transaction, and there is no central body to quickly fix or freeze affected funds. The new research shows the threat could arrive sooner than many expected. Google has been preparing for quantum-safe methods for years and wants the crypto world to start moving now.
When will this happen?
There is no danger today. Current quantum computers are still small and too error-prone. However, Google has set 2029 as its own deadline to switch its systems to quantum-resistant security. Experts now see a real possibility of capable machines appearing in the early 2030s.
Simple steps for now include avoiding reuse of addresses and rotating keys where possible. In the long run, blockchains will need to adopt new quantum-safe signature methods. The message is calm but clear: the crypto community should begin preparing without delay.
