Google’s new research reveals that quantum computers may require less power to break the cryptography protecting Bitcoin (BTC) and Ethereum (ETH) blockchains. The research estimates that this cryptography can be broken with fewer than 500,000 physical qubits based on current hardware assumptions.
Technical Details of Google’s Quantum Research
In a test of a cryptographically relevant quantum computer (CRQC) based on superconducting qubits, a 20-fold reduction in the number of qubits was achieved for the 256-bit elliptic curve discrete logarithm problem (ECDLP-256), which is widely used in cryptocurrency blockchains. This is an optimization beyond traditional estimates; Google Quantum AI increased qubit efficiency with error correction algorithms and hybrid approaches. ECDLP plays a fundamental role in deriving public keys from private keys and becomes breakable with quantum algorithms like Shor’s in parallel computations.
Risk of On-Spend Attack on Bitcoin
In a theoretical scenario specific to BTC, a quantum computer can perform an “on-spend attack” within Bitcoin’s 10-minute block time by breaking a private key in as little as 9 minutes. This is critical when reusing addresses during spending; the attacker can redirect funds to their own wallet. The graph shows the success probability:
Graph showing the risk that an on-spend quantum attack that takes 9 minutes to derive a private key succeeds against Bitcoin. Source: Google Quantum AI
Ethereum’s Sensitivity to At-Rest Attacks
ETH is structurally sensitive to “at-rest attacks”; the public key becomes permanently visible on the blockchain in the first transaction. The richest 1,000 exposed ETH accounts (containing approximately 20.5 million ETH) can be broken in less than 9 days. This, as we emphasized on our ETH detailed analysis pages, increases the risk of old addresses.
Current ETH Price and Technical Levels
As of March 31, 2026, ETH price is $2,057.59, 24-hour change +0.58%. RSI 48.05 (neutral), trend sideways, Supertrend bearish. EMA 20: $2,076.41.
| Level | Price | Score | Distance | Sources |
|---|---|---|---|---|
| S1 | $1,939.78 | 71/100 ⭐ | -5.84% | S3, Donchian Lower, Fibo 0.114 |
| S2 | $2,023.20 | 67/100 ⭐ | -1.79% | Prev Day Close, Swing L |
| R1 | $2,149.67 | 67/100 ⭐ | +4.35% | HVN 5, Ichimoku Kijun, Fibo 0.214 |
| R2 | $2,066.15 | 65/100 ⭐ | +0.30% | POC, Ichimoku Tenkan |
Quantum news may affect ETH futures volatility; similar BTC spot analysis is recommended for BTC.
Urgent Transition to Post-Quantum Cryptography
Google recommends an urgent transition of blockchains to post-quantum cryptography (PQC) and sets 2029 as the deadline. Ethereum researcher Justin Drake sees the probability of Q-Day (quantum supremacy day) by 2032 as over 10%. Integration of lattice-based algorithms like NIST standards (Kyber, Dilithium) is essential.
Source: https://en.coinotag.com/google-quantum-threat-can-eth-and-btc-be-broken
