Bitcoin and Quantum Computing: Tom Lee Warns 35% of BTC Could Be at Risk by 2028

Tom Lee, co-founder of Fundstrat Global Advisors, has just issued a warning that is sending shockwaves through the crypto community: 35% of Bitcoin’s total supply could be vulnerable to a quantum attack by 2028. A projection that reads like a countdown for BTC holders.

But behind this anxiety-inducing figure lies a far more nuanced technical debate. Adam Back, a first-generation cypherpunk and one of the most influential figures in the Bitcoin ecosystem, is directly challenging the logic behind this warning. Between media panic and cryptographic reality, the gap is enormous.

Who is right? And more importantly, what real risk does the Bitcoin network actually face today as quantum computing continues to advance?

Tom Lee and the Quantum Threat: What the Numbers Really Say

Tom Lee bases his warning on a precise technical observation: approximately 35% of bitcoins in circulation are stored in so-called “exposed” addresses, meaning P2PK (Pay-to-Public-Key) addresses or reused addresses whose public key is visible on-chain. And it is precisely this public key that a sufficiently powerful quantum computer could exploit to derive the private key using Shor’s algorithm.

The 2028 window put forward by Lee is not arbitrary. It aligns with several academic and industry projections estimating that quantum machines capable of breaking ECDSA (Elliptic Curve Digital Signature Algorithm) — the cryptographic standard used by Bitcoin — could emerge within this decade. Google, IBM, and state-backed players are investing heavily in this race. Quantum computing power roughly doubles every two years, according to data published by the research teams at these major tech giants.

This scenario primarily affects Satoshi Nakamoto‘s bitcoins — estimated at around 1 million BTC — whose P2PK addresses directly expose the public key. It also concerns all users who have reused the same Bitcoin address multiple times, a common practice in the early years of the network.

Adam Back Dismantles the Panic: Why Bitcoin Is Not Defenseless

Adam Back, inventor of Hashcash and CEO of Blockstream, does not deny the reality of the long-term quantum threat. But he points to a major flaw in the alarmist reasoning: Bitcoin can evolve. The protocol is not set in the cryptographic stone of 2009.

The Bitcoin developer community is actively working on post-quantum cryptography solutions. Proposals such as Lamport signatures and schemes based on lattice-based cryptography are already under review as part of the NIST standardization process. Back also emphasizes that a migration of vulnerable addresses to quantum-resistant addresses could be orchestrated well before the threat becomes operational — provided the community acts with sufficient foresight.

The real risk, according to Back, is not technical but behavioral: inactive holders of old bitcoins — some of which are likely lost forever — will never migrate their funds. That is where the structural vulnerability lies, not in any inability of the protocol to adapt. The question is therefore not “Can Bitcoin survive the quantum era?” but rather “How many BTC will be left behind during the transition?”

What Bitcoin Holders Need to Know Today

For current holders, the practical takeaway is clear: avoid reusing a Bitcoin address and favor address formats such as SegWit (bech32) or Taproot, which do not expose the public key prior to a transaction being signed. These formats offer an additional layer of protection in a scenario where quantum computing power gradually increases.

On the macroeconomic front, Tom Lee‘s warning comes at a time when narratives around Bitcoin’s security directly influence market sentiment. Selling pressure driven by poorly calibrated quantum fears could create opportunities for well-informed investors — or trigger brutal volatility for those reacting on emotion rather than analysis.

The 2028 horizon remains speculative. No operational quantum computer today has the processing power required to threaten ECDSA-256. Quantum cryptography experts generally estimate that several million stable logical qubits would be needed — whereas current machines top out at a few thousand noisy physical qubits. The countdown exists, but it has not yet begun.