In a striking assertion, the co-founder of a major crypto-analytics firm describes quantum computing as the greatest long-term threat facing Bitcoin. According to him, the cryptographic foundations that underpin Bitcoin—especially the relationship between private and public keys—could one day be undermined by quantum machines, potentially exposing user funds and shaking trust in the network.
At the heart of the concern is how Bitcoin’s security works: a private key is used to derive a public key via elliptic-curve math (specifically the secp256k1 curve); as long as the math remains infeasible to reverse with classical computers, the system holds strong. However, quantum computing threatens to change that calculus.
Once a quantum machine becomes capable of deriving private keys from public keys within realistic timeframes, the so-called “one-way function” model is broken. The analyst warns that when a Bitcoin address spends its output, it reveals its public key to the network, increasing vulnerability. Prior to spending, many addresses remain hashed and thus somewhat quieter targets, but once active they may become exposed.
Computer potential and risks
He emphasizes that this is not science fiction but a genuine risk requiring active mitigation. Developers, network stakeholders and the wider community need to treat the quantum threat as urgent—planning for post-quantum cryptography, alternate signature schemes and migration paths for “exposed” coins. While actual quantum-cryptographic attacks remain theoretical today, the time window to prepare is finite.
The longer key-reuse continues, the larger the pool of coins at risk. In short, Bitcoin’s very trust model—its ability to rely on math and decentralisation—must evolve. If it doesn’t, the biggest challenger it may face is not another blockchain, regulation or macro-economic shock—it may be quantum computing itself.
