Here’s a fun thought experiment: what if someone could just… guess your Bitcoin private key? Not through brute force, not through social engineering, but through math so advanced it makes today’s encryption look like a diary lock. That’s the quantum computing threat to Bitcoin, and according to Galaxy Digital, roughly $470 billion worth of BTC is sitting in the blast radius.
A March 2026 research note from Galaxy Digital, building on analysis from Project Eleven, estimated that approximately 7 million BTC are held in what researchers call “long exposure” addresses. These are addresses whose public keys have already been revealed on-chain, meaning they’ve been used to send transactions at least once. That exposure is the critical detail.
Why exposed public keys matter
Think of Bitcoin security like a two-lock system. Your public address is derived from your public key, which is derived from your private key. When you’ve never sent a transaction, the world only sees your address. Your public key stays hidden behind a layer of hashing, which even quantum computers can’t easily reverse.
But the moment you sign a transaction, your public key gets broadcast to the network. For classical computers, working backwards from a public key to a private key is essentially impossible. For a sufficiently powerful quantum computer running Shor’s algorithm, it becomes a solvable math problem.
