A new dataset from analytics firm Glassnode has put a precise number on one of the longest-running theoretical threats to Bitcoin: approximately 7.12 million BTC — equal to 35.4% of the entire circulating supply — sits in wallets whose public keys are already visible on the blockchain, making them potentially vulnerable to a sufficiently powerful quantum computer. The finding reframes what has historically been treated as a distant, speculative danger into something with a measurable footprint on the ledger right now.
To understand why this matters, it helps to understand what a public key actually is. In Bitcoin's cryptographic architecture, every wallet has a private key — the secret that authorizes spending — and a corresponding public key, which is mathematically derived from it. Under normal wallet behavior using modern address formats, the public key is never broadcast to the ledger until the moment a transaction is signed. That design keeps the public key hidden, and without it, even a theoretical quantum attacker has nothing to target. But millions of coins were sent to address formats — most notably older Pay-to-Public-Key (P2PK) addresses and early reused Pay-to-Public-Key-Hash (P2PKH) addresses — that either embed the public key directly or expose it the first time funds are spent. Those coins are what Glassnode has now counted and catalogued.
The quantum threat to public-key cryptography is not science fiction, but neither is it imminent. Current quantum computers, including the most advanced machines from Google and IBM, operate at error rates too high and qubit counts too low to run Shor's algorithm at the scale required to crack a 256-bit elliptic curve key — the standard underpinning Bitcoin's signature scheme. Most serious cryptographers place a credible quantum threat to Bitcoin's existing key infrastructure somewhere between a decade and several decades away. But the operative word is "credible," not "impossible," and the Glassnode data makes clear that a substantial portion of the supply would be in the blast radius if that timeline accelerates.
For the vast majority of holders whose coins appear in this exposure count, the fix is straightforward and available today. Moving funds from an exposed address to a fresh wallet — one that uses SegWit or Taproot address formats that keep the public key hidden until spend — eliminates the vulnerability entirely. The operation takes minutes, costs a small transaction fee, and requires no technical expertise beyond basic wallet navigation. The Bitcoin community has repeatedly encouraged this migration, and modern wallet software defaults to safer address formats automatically. The problem is behavioral, not technical: coins sit unmoved because their owners either don't know about the risk, don't consider it urgent, or have simply lost access to the wallet entirely.
That last category is where the story takes its most consequential and irreversible turn. A significant portion of the exposed supply almost certainly belongs to wallets whose private keys are lost forever — coins from the earliest days of the network, mined when Bitcoin had no monetary value and stored with little regard for long-term security hygiene. Among those coins are the wallets attributed to Bitcoin's pseudonymous creator, Satoshi Nakamoto. Estimates of Satoshi's holdings typically cluster around one million BTC, mined in the network's first year using P2PK outputs that expose the public key by design. Those coins have never moved. No one alive can move them. And under a future quantum-capable attack scenario, they represent a uniquely permanent vulnerability — one that cannot be patched, migrated, or remediated without the private key that may no longer exist in any recoverable form.
The Satoshi coins occupy a strange dual role in Bitcoin's mythology. They are simultaneously treated as proof of the founder's restraint — coins left untouched for over fifteen years — and as an existential asterisk on the network's long-term security model. If a quantum computer were ever to crack those exposed public keys and move those coins, the market and psychological consequences would extend far beyond the monetary value of the BTC itself. It would represent a fundamental breach of Bitcoin's foundational promise: that properly secured coins cannot be taken.
The Bitcoin development community has not been idle on this front. Research into post-quantum cryptographic signature schemes — including lattice-based alternatives that would resist quantum attacks — has accelerated alongside the broader cryptographic standards work being finalized by the United States National Institute of Standards and Technology (NIST). Integrating any such scheme into Bitcoin would require a network-wide upgrade, a soft or hard fork of significant political and technical complexity. No concrete proposal has achieved consensus, but the conversation has moved from theoretical white papers to active developer discussion.
What the Glassnode data ultimately delivers is an inventory of urgency. 7.12 million BTC is not an abstraction — it represents hundreds of billions of dollars in value at current market prices, sitting in an exposure class that the network's future security upgrades may not be able to reach in time for every coin. For active holders whose funds appear in that count, the message is unambiguous: migration is free, fast, and available right now. For the broader ecosystem, the data is a forcing function — a reason to treat post-quantum Bitcoin development not as a long-horizon curiosity but as infrastructure work with a visible and measurable deadline.
Written by the editorial team — independent journalism powered by Bitcoin News.