Tom Lee warns quantum computers could threaten Bitcoin by 2028

The debate over quantum computing and Bitcoin security is back in the spotlight.

Fundstrat co-founder Tom Lee recently warned that powerful quantum computers could begin threatening Bitcoin within the next few years. He believes the technology may become advanced enough by 2028 or 2029 to break parts of Bitcoin's current security system.

His comments have sparked fresh discussions across the crypto industry. However, several Bitcoin developers say the situation is more complex than it first appears.

Tom Lee Says Quantum Computing Could Challenge Bitcoin

During a recent interview, Tom Lee said rapid progress in quantum computing could create new risks for Bitcoin.

He pointed to research suggesting that future quantum computers may be able to solve mathematical problems much faster than today's computers.

If that happens, some of Bitcoin's security methods could become vulnerable. Lee also suggested that blockchain networks such as Ethereum and Solana may be better prepared to respond to future quantum threats.

Bitcoin Experts Say the Risk Is Often Misunderstood

Not everyone agrees with Lee's warning.

Adam Back, the creator of Hashcash and one of Bitcoin's earliest developers, responded by explaining that Bitcoin does not rely on traditional encryption to process transactions. Instead, Bitcoin uses digital signatures to prove ownership of coins.

He also noted that Bitcoin seed phrases are protected by extremely large amounts of randomness, making them impossible for current computers to guess.

According to Back, quantum computers cannot simply break every Bitcoin wallet overnight.

Only Older Bitcoin Wallets Face the Biggest Risk

Experts say the main concern involves older Bitcoin addresses.

When Bitcoin is spent from certain older wallets, the public key becomes visible on the blockchain. A future quantum computer powerful enough to run Shor's algorithm could theoretically calculate the matching private key from that public key.

This could allow an attacker to steal coins from those wallets.

Researchers estimate that around 30% to 35% of all Bitcoin, or roughly 7 million BTC, could fall into this category because the coins are stored in older or reused addresses. Modern Bitcoin wallets reduce this risk by generating new addresses for each transaction.

Can Bitcoin Prepare for Quantum Computing?

Many developers believe Bitcoin has time to prepare. Quantum computers powerful enough to attack Bitcoin do not exist today.

If the technology continues to improve, the Bitcoin community could upgrade the network to use quantum-resistant cryptography before large-scale attacks become possible.

Similar discussions are already taking place across the broader blockchain industry as researchers prepare for future advances in computing.

What Bitcoin Investors Should Watch

Tom Lee's warning highlights a long-term challenge rather than an immediate threat.

While quantum computing continues to advance, most experts agree that today's Bitcoin network remains secure. The biggest risk applies mainly to older wallet addresses with exposed public keys, not to every Bitcoin holder.

For now, investors should follow developments in both quantum computing and Bitcoin research as the industry continues working on future security upgrades.