StarkWare researcher Avihu Levy has published a paper introducing Quantum Safe Bitcoin (QSB), a scheme that lets users execute quantum-resistant transactions without changing Bitcoin's underlying protocol. The core idea: replace signature-based security with hash-based proofs, eliminating the vulnerability that quantum computers could exploit to derive private keys from public keys.
Hash proofs replace ECDSA, bypassing hard forks
Bitcoin currently relies on ECDSA signatures, where a user signs with a private key and miners verify with the public key. A sufficiently powerful quantum computer could reverse this process, deriving the private key from the public key and stealing funds. QSB sidesteps this risk by using hash-based proofs—mathematical fingerprints that are computationally infeasible to forge on both classical and quantum machines.
The scheme works within Bitcoin's existing consensus rules. No BIP-360-style soft fork or network-wide activation is required. Levy notes that BIP-360, though a more permanent solution, has yet to be included in Bitcoin Core and would take years to deploy if approved. QSB bypasses those political and technical roadblocks entirely.
$75–200 per transaction, and you still have to find a miner
The trade-off is steep. Each QSB transaction requires intensive GPU-based cloud computation, sifting through billions of candidates before finding a valid hash. Levy estimates costs of $75 to $200 per transaction, compared to Bitcoin's current average fee of around $0.33. Users cannot broadcast QSB transactions through normal channels; they must directly contact miners willing to process them. Integrating with Lightning Network or other low-cost scaling solutions is currently impractical.
Specialized hardware and technical expertise are also required, putting QSB out of reach for most ordinary holders. Levy emphasizes that the scheme is a "last resort" for when a genuine quantum threat emerges. Users could temporarily move funds to QSB addresses while waiting for a permanent protocol-level fix like BIP-360. Most experts agree that a quantum computer capable of breaking Bitcoin's cryptography is unlikely to materialize in the near term. Still, QSB offers an emergency exit for those willing to pay the price.