Quantum-safe bitcoin now possible without a soft fork, but costs $200 a pop, new research shows A new scheme from a StarkWare researcher works under existing consensus rules, offering an emergency fallback while BIP-360 awaits activation. What to know: - A StarkWare researcher has proposed Quantum Safe Bitcoin, a hash-based scheme that can make bitcoin transactions resistant to quantum attacks today without changing the Bitcoin protocol. - The method works within existing consensus rules but requires massive off-chain GPU computation, driving estimated costs to $75 to $200 per transaction and making it far more complex than standard payments. - Framed as a last-resort emergency tool rather than a permanent fix, QSB contrasts with long-term proposals like BIP-360, which seek protocol-level quantum resistance but are likely years away from activation. A StarkWare researcher has published what he says is the first method for making bitcoin transactions quantum-safe on the live network today, without any changes to the Bitcoin protocol. The scheme, however, costs up to $200 per transaction and is designed as an emergency measure rather than a permanent fix. In a paper published this week, StarkWare researcher Avihu Levy introduced Quantum Safe Bitcoin, or QSB, a scheme that aims to enable quantum-resistant transactions without requiring changes to the Bitcoin protocol, by replacing signature-based security assumptions with hash-based proofs within its design. The hash-based design survives the kind of quantum attack that would break today’s cryptography, but shifts the burden from consensus to computation, requiring heavy off-chain GPU work for every transaction. Think of traditional digital signatures as a handwritten signature on a cheque, which proves you authorized a transaction using a secret key that others can cross check with a public key. In Bitcoin, these digital signatures are called ECDSA signatures. They are secure against today’s computers, but a sufficiently