U.S. Government Plans More Than $2 Billion Quantum Push, Raising Bitcoin and Ethereum Security Concerns

Bitcoin transactions rely on elliptic-curve digital signatures. A sufficiently powerful quantum computer could use Shor's algorithm to derive a private key from a public key, leaving older addresses whose keys have already been exposed at greatest risk. A February 2026 estimate put nearly 7 million BTC at risk, including about 1 million attributed to Satoshi Nakamoto, with a combined value of about $440 billion. The issue has implications for holders' property rights and consensus across the network.

On June 13, 2026, an independent quantum computing advisory board convened by Coinbase said quantum computers could not yet break Bitcoin but urged immediate planning for quantum-resistant signatures. It estimated that about 6.7 million BTC was at risk but did not endorse freezing or restricting older coins. A May 6 report from Project Eleven set 2033 as its baseline year for Q-Day, with 2030 as the earliest scenario.

Bitcoin transactions use elliptic-curve digital signatures to secure assets. A quantum computer running Shor’s algorithm could potentially derive private keys from public keys, putting older wallets and transaction security at risk. Ethereum, by contrast, has planned a mechanism allowing accounts to adopt quantum-resistant signatures, bringing corporate crypto treasury strategies and onchain governance capabilities into focus.

Google Quantum AI and other institutions published research on March 30, 2026, estimating that fewer than 500,000 physical qubits could crack a key in about nine minutes. Citi warned on May 18 that the potential attack timeline had shortened. Bit Digital had already announced on July 7, 2025, that it would sell about 280 Bitcoin and, alongside a $172 million fundraising, increase its holdings to 100,603 Ethereum.

Bitcoin uses elliptic-curve cryptography to protect assets and communications, but sufficiently powerful quantum computers could eventually break its current encryption. Experts say the more immediate danger is a “harvest now, decrypt later” strategy, in which attackers intercept and store large volumes of encrypted communications today, then recover sensitive historical data once the technology matures. The threat extends beyond wallet private keys.

Security experts and an early-stage venture investor have recently warned that historical communications and infrastructure data across the Bitcoin ecosystem may already be targets for quantum attacks. Ethereum has begun work on a post-quantum migration, but as of this report, neither Bitcoin nor related companies had publicly committed to specific safeguards, disclosed investment amounts or set completion dates. The upgrade timetable and division of responsibility therefore remain unclear.

Bitcoin and Ethereum rely on elliptic-curve cryptography to safeguard assets. A quantum computer capable of deriving a private key from a public key could potentially steal funds. Bitcoin activated Taproot on November 14, 2021, and because some transactions expose public keys in advance, the potential window for attack has widened.

The latest research from Google Quantum AI estimates that about 500,000 error-corrected physical qubits could be enough to crack a key within Bitcoin’s roughly nine-minute transaction confirmation window, far below previous estimates of several million qubits. No funds have been reported stolen through such an attack, but the researchers are urging the community to begin planning a migration to post-quantum cryptography.

Ethereum uses elliptic-curve cryptography, or ECC, to secure wallets and transactions, but advances in quantum computing could undermine that foundation. Google’s Quantum AI team and Ethereum researchers said most Layer 2 networks, DeFi protocols and whale wallets do not yet have quantum-resistant protections, leaving more than $100 billion in assets potentially at risk.

As of July 19, 2026, the latest report identified five major attack paths, including deriving private keys, seizing DeFi administrator privileges and attacking staking systems. Google also warned that the resource threshold for using quantum computers to break ECC had fallen 20-fold. Some attacks could take minutes, a substantial reduction from previous estimates.

Quantum computers capable of using Shor’s algorithm to break elliptic-curve cryptography could derive private keys from public keys, threatening trillions of dollars in assets on Bitcoin, Ethereum and Solana. Although the risk is not imminent, migration could take years and would require decisions on legacy coins as well as community consensus. Early preparation has therefore become a core security priority.

A March 28, 2026, report said the Ethereum Foundation has operated a quantum research team since 2025 and is planning a phased rollout of post-quantum signatures and LeanVM. Bitcoin has proposed BIP360 to allow funds to move gradually to more secure addresses. Solana tested the Project Eleven-led Winternitz Vault in December 2025. The three networks still have no common timeline.

PsiQuantum is seeking to scale quantum computing with silicon photonics and plans to build a system containing 1 million “physical qubits.” That is not the same as 1 million directly usable logical qubits. But if error correction and computing capabilities mature in tandem, the system could threaten Bitcoin’s current digital signatures, prompting debate over asset custody, address migration and cryptographic upgrades.

PsiQuantum recently broke ground in Chicago on its first facility designed for 1 million physical qubits and secured more than $1 billion in funding led by Nvidia. Reports said the company is targeting commercial operations as early as 2027, with the full facility expected to become operational around 2028. It has not yet demonstrated the fault-tolerant quantum capabilities needed to break Bitcoin signatures.