Cathie Wood's Ark Invest says quantum computing is a long-term risk for bitcoin, not an imminent threat

• Ark Invest said current quantum computers lack the power needed to break Bitcoin’s cryptography, and meaningful breakthroughs would likely affect broader internet security first.
• Roughly 35% of the bitcoin supply sits in address types theoretically vulnerable to future quantum attacks, though about 1.7 million BTC is likely already lost.
• Any quantum risk would unfold through visible technological milestones over the years, giving Bitcoin developers time to implement upgrades such as post-quantum cryptography, the report said.

Asset manager Ark Invest says quantum computing is a long-term consideration for Bitcoin security but not an imminent threat.

In a Wednesday report co-authored with Unchained, the investment manager said today’s quantum computers are far below the capabilities needed to break Bitcoin’s cryptography, which relies on elliptic curve encryption to secure wallets.

“Today’s quantum systems lack the capabilities required to compromise Bitcoin,” wrote authors Dhruv Bansal, co-founder and CSO at Unchained; Tom Honzik, director of custody research at Unchained; and David Puell, research trading analyst and associate portfolio manager for digital assets at Ark Invest.

Even if quantum systems eventually reach that level, the risks will likely emerge gradually and at high cost to attackers, the report said.

One of the main reasons Bitcoin won't face an immediate threat is because a major breakthrough in quantum computing would likely disrupt broader internet security first, prompting coordinated responses from governments, technology firms and financial institutions before reaching Bitcoin.

The report comes as long-term investors grapple with the possibility that advances in quantum computing could one day break the cryptography underpinning bitcoin, fueling speculation about a potential security crisis.

Earlier this year, a prominent portfolio strategist at Jefferies, Christopher Wood, said investors should drop 10% bitcoin allocation and add gold instead, due to a quantum threat. The move rattled investors and spooked the digital assets market.

35% of the supply in risk

While researchers broadly agree that such capabilities remain far off, the prospect that powerful quantum machines could eventually crack private keys or older wallet formats has raised concerns among investors about long-term risks to bitcoin and the broader digital asset ecosystem.

Ark's report estimated that about 35% of bitcoin’s supply sits in address types theoretically exposed to future quantum attacks, including roughly 1.7 million BTC believed to be lost and about 5.2 million BTC that could be migrated to more secure wallets.

One of those wallets, roughly 1 million BTC, belongs to Satoshi Nakamoto, the creator of the Bitcoin network.

However, rather than a sudden “Q-day,” Ark Invest sees these progressions unfolding in several different stages over many years. Some investors fear the first attack could occur before 2030, while others suggest it could be "decades away," the report noted.

The report argues that in either scenarios, it will likely give the Bitcoin community time to upgrade the network with quantum-resistant cryptography and encourage users to move coins to safer address formats.

"The good news is that we already know how to protect against quantum attacks," the report said.

"The majority of Bitcoin’s supply is held in quantum-resistant addresses, and the remainder is held in quantum-vulnerable addresses that should not be at risk until Stage 3 of our timeline, when a CRQC exists that can break a 256-bit ECC key."

The world’s largest cryptocurrency was trading around $70,000 at the time of publication.

Read more: Grayscale sees regulation, not quantum fears, shaping crypto markets in 2026

• Ethereum co-founder Vitalik Buterin argues the network’s most fundamental role may be as a decentralized “public bulletin board” that stores and shares data for cryptographic systems like secure voting and certificate management.
• Buterin says upgrades such as PeerDAS are boosting Ethereum’s data capacity, while ETH payments and smart contracts help prevent spam and enable secure coordination across decentralized apps.

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