Quantum-Safe Bitcoin: StarkWare’s New ‘No Soft Fork’ Defense

• StarkWare researcher Avihu Levy is behind the Quantum Safe Bitcoin (QSB) proposal.
• Instead of changing Bitcoin itself, QSB runs entirely within the network’s current rules.
• Transactions could cost $75 to $150 in computing power, far more than normal Bitcoin fees.

StarkWare’s new research proposal is stirring up the conversation about Bitcoin’s future security, suggesting that the network could fend off quantum computing threats without a disruptive, hard fork‑style upgrade.

The proposal, put forward by StarkWare researcher Avihu Levy, is called Quantum Safe Bitcoin (QSB). It’s a way to protect transactions from future quantum computers using Bitcoin’s existing infrastructure.

Right now, Bitcoin’s security relies heavily on elliptic curve cryptography (ECDSA), which protects wallets and transactions. However, a quantum computer powerful enough could, in theory, crack that system with Shor’s algorithm, exposing private keys and allowing attackers to steal funds.

This risk isn’t new and has been discussed for years, but fixing it has usually meant big protocol changes (like soft or hard forks), which are slow and complex.

Levy’s proposal takes a different approach. Instead of changing Bitcoin itself, QSB runs entirely within the network’s current rules, so it could be rolled out immediately without requiring consensus from miners or developers.

StarkWare co‑founder Eli Ben‑Sasson was ecstatic with the proposal and backed the work, saying Bitcoin could be quantum‑safe right now.

How Quantum-Safe Bitcoin Works

The key breakthrough is swapping out Bitcoin’s elliptic curve signatures for hash‑based cryptographic puzzles.

Rather than using a normal signature to prove ownership, users generate a transaction whose hash output accidentally matches a valid signature format. It’s all based on brute‑force computing, rather than fragile cryptographic assumptions.

Since quantum computers only get a limited speed boost against hash functions (through Grover’s algorithm), this approach stays resistant even after quantum computing arrives.

According to the research, the system achieves up to roughly 118-bit security against quantum attacks.

High Costs and Limited Usability

Despite its breakthrough potential, the proposal comes with notable limitations. For instance, each transaction could cost $75 to $150 in computing power, significantly more than normal Bitcoin fees.

It also needs specialized tools and GPUs, and doesn’t support common use cases like the Lightning Network. Moreover, this system would only protect new outputs and not old wallets already visible on‑chain.

As such, the StarkWare researcher himself describes QSB as a last resort solution, mainly useful for protecting big transactions or large crypto holdings.

Related: Nobel Physicist Warns Quantum Computing Could Hit Bitcoin Soon