Crypto Isn’t Safe Forever: Coinbase Advisory Board Flag Quantum Risk to 6.9 Million BTC

A Coinbase-commissioned advisory board has warned that advances in quantum computing could eventually undermine the cryptographic signatures that secure proof-of-stake (PoS) blockchain networks, highlighting a long-term but increasingly serious security challenge for the digital asset industry.

The report, released on April 21 by Coinbase’s Independent Advisory Board on Quantum Computing and Blockchain, examines how future quantum computing capabilities could impact core blockchain security assumptions. While the board stressed that cryptocurrencies remain secure under current technological conditions, it said the industry must begin preparing for a post-quantum cryptography transition.

The advisory group includes prominent figures from academia and the crypto industry, including Professor Scott Aaronson of the University of Texas at Austin, Professor Dan Boneh of Stanford University, Ethereum researcher Justin Drake, EigenLayer founder Sreeram Kannan, Coinbase cryptography head Yehuda Lindell, and Professor Dahlia Malkhi of the University of California, Santa Barbara.

According to the report, there is “high confidence” that sufficiently powerful quantum computers will eventually be built that could break the cryptographic systems underpinning blockchain networks. While experts generally expect such capability to be at least a decade away, the board cautioned that shorter timelines cannot be ruled out.

Wallet-Level Exposure, Not Core Blockchain Design

The report distinguishes between different layers of blockchain security, noting that Bitcoin’s core infrastructure—its mining process, hash functions, and historical ledger—remains largely resilient to quantum attacks.

Instead, the primary vulnerability lies at the wallet and signature level, where public-key cryptography is used to prove ownership of digital assets. Wallets with exposed public keys are considered the most at risk under a future quantum computing scenario.

The report estimates that approximately 6.9 million BTC could fall into categories potentially vulnerable to such exposure, particularly funds held in addresses where public keys are already visible on-chain.

Proof-of-stake networks, including Ethereum, face an additional layer of exposure. In these systems, validator signatures are central to securing consensus, meaning that a sufficiently powerful quantum computer could theoretically compromise validator authentication mechanisms if cryptographic standards remain unchanged.

Migration to Quantum-Resistant Systems Remains a Challenge

While quantum-resistant cryptographic solutions are already under development, the report emphasizes that implementation at scale remains a significant coordination challenge. Post-quantum signature schemes are typically larger, which could increase transaction sizes, slow processing speeds, and raise storage and computational costs across blockchain networks.

The advisory board warned that migrating millions of wallets to new cryptographic standards would require broad user participation and careful protocol design, making the transition both technically and socially complex.

It also highlighted a difficult policy question for blockchain networks: how to handle assets stored in lost keys, inactive wallets, or abandoned accounts, which may never be upgraded to quantum-safe standards but could still become vulnerable in a future quantum environment.

Differing Timelines Across Blockchain Ecosystems

The report notes that several blockchain ecosystems are already exploring quantum-resistant pathways. Networks such as Solana, Algorand, and Aptos are among those either researching or integrating alternative cryptographic approaches aimed at reducing future quantum exposure.

Bitcoin and Ethereum developers, meanwhile, are also beginning to outline long-term migration strategies, though no immediate protocol changes are currently required given the state of quantum computing technology today.

Industry-Wide Early Warning

The Coinbase advisory board’s findings align with broader warnings emerging from the technology sector. Earlier concerns from major tech firms, including Google, have suggested that sufficiently advanced quantum computers could eventually break widely used cryptographic systems, reinforcing the need for early preparation rather than reactive fixes.

Despite the long timeline, the report’s central message is clear: quantum computing is not an immediate threat, but it represents a structural risk that could reshape blockchain security models in the future—particularly for proof-of-stake networks reliant on digital signature schemes.