StarkWare said an experimental Bitcoin transaction designed to resist future quantum attacks has been mined on the Bitcoin mainnet. According to the company, the test used Bitcoin’s current rules rather than relying on a change to the network’s consensus system.

The method is based on what StarkWare calls Quantum-Safe Bitcoin, or QSB, a hash-based approach intended to protect specific transactions. StarkWare presented the result as an interim technique for securing some funds while broader changes to Bitcoin remain unresolved.

How the method works

StarkWare said QSB allows a transaction to be accepted by Bitcoin without altering the protocol itself. The system uses off-chain computation to search for a transaction hash that the network will treat as a validly formatted signature.

The company described this process as “signature grinding.” StarkWare said the method was developed by researcher Avihu Levy and later turned into a working mainnet transaction with help from engineer Tomer Giladi.

Limited protection, not a full fix

StarkWare said the experiment does not make Bitcoin as a whole quantum-safe. Instead, it is designed to protect individual transactions under certain conditions while the broader network continues to operate as it does today.

The company also said the approach cannot protect addresses whose public keys have already been exposed. That limitation is significant because the technique is aimed at reducing a future risk, not reversing exposure that has already happened.

Operational constraints remain

In its current form, QSB also comes with practical limits. StarkWare said transactions using the method must be sent directly to miners, rather than handled through the normal path used by standard Bitcoin transactions.

That means the system is still experimental and not yet a general-purpose solution for ordinary network use. The mainnet test shows that the concept can work within Bitcoin’s existing framework, but it does not remove the barriers to wider deployment.

What comes next

StarkWare said a soft fork remains the preferred long-term option for giving Bitcoin a network-wide defense against quantum threats. By contrast, QSB is positioned as a temporary or partial measure that could help protect some holdings before any broader upgrade is adopted.

For now, the confirmed milestone is the mined mainnet transaction itself. The larger question of how Bitcoin might implement system-wide quantum protection, if it does, remains open.

Source: decrypt.co