A Bitcoin researcher has proposed a scheme to make transactions resistant to quantum computer attacks without changing Bitcoin’s core protocol. The method, called Quantum Safe Bitcoin (QSB), replaces vulnerable cryptographic signatures with a computationally intensive hash puzzle. However, the approach is costly at $75 to $150 per transaction and is considered a temporary, last-resort measure suitable only for large transfers.
A Bitcoin researcher has developed a method to make transactions quantum-safe without requiring a network upgrade. Avihu Levy, chief product officer at StarkWare, published the proposal for Quantum Safe Bitcoin (QSB) transactions.
The scheme operates within Bitcoin’s existing script constraints and is designed to remain secure against an adversary with a quantum computer. It replaces the proof-of-work signature puzzle with a hash-to-sig puzzle that requires brute-force computation.
This computational burden is a security feature that even a quantum computer cannot shortcut. However, the proposal comes with significant practical caveats for everyday use.
Each QSB transaction costs the sender between $75 and $150 in computing resources. The complexity and cost mean it likely only makes sense for securing large Bitcoin transactions.
Eli Ben-Sasson, CEO of StarkWare, said the proposal is “huge” and essentially makes Bitcoin quantum-safe today. Other community members noted limitations with the approach.
Bitcoin ESG specialist Daniel Batten said calling it a complete solution was “an overstatement”. He noted exposed public keys and an estimated 1.7 million BTC in early addresses are not addressed.
The researchers acknowledged QSB is a last-resort measure as transactions are non-standard and costs don’t scale. They concluded that protocol-level changes remain the preferred long-term path for quantum security.
The debate occurs alongside other developments in quantum-proofing Bitcoin. Lightning Labs CTO Olaoluwa Osuntokun recently published a prototype for a quantum “escape hatch” for wallet ownership proofs.
