StarkWare researchers have published an open-source scheme to make Bitcoin transactions resistant to quantum computing attacks using only the network’s existing consensus rules. No soft forks, protocol upgrades, or community-wide coordination required.
The project, called Quantum Safe Bitcoin (QSB), was released on GitHub by Avihu Levy, StarkWare’s chief product officer and the company’s leading Bitcoin researcher, who previously co-wrote ColliderScript, a protocol that enables stateful computation on top of Bitcoin without changing consensus. Levy is also a co-author of BIP-360, a quantum-resistant address proposal that was integrated into Bitcoin’s official BIP repository in February. This proposal, unlike QSB, requires a soft fork.
“StarkWare has some of the best hackers on the planet,” Eric Wall, co-founder of Taproot Wizards and director of the Starknet Foundation, wrote on X. “It’s beautiful to see hackers use their power for good.”
QSB is built on Binohash, a transaction introspection technology developed by BitVM creator Robin Linus of ZeroSync and Stanford University, and was demonstrated on Bitcoin mainnet in February.
No soft fork required
The lack of soft forks sets QSB apart. Most paths to hardening Bitcoin against quantum attacks, including hash-based signature schemes like BIP-360 and SPHINCS+, require protocol-level changes to navigate Bitcoin’s notoriously slow and contentious governance process.
More and more people are seeing this governance bottleneck as a real vulnerability. A Google Quantum AI paper published on March 30 concludes that fewer than 500,000 physical qubits may be needed to crack Bitcoin’s elliptic curve cryptography, which is about a 20x reduction from previous estimates. The paper warned that a sufficiently sophisticated machine could derive a private key from a published public key in about nine minutes, which could just put it within Bitcoin’s 10-minute block window. Google itself has set a deadline of 2029 to transition its authentication services to post-quantum cryptography.
QSB avoids governance issues completely. The scheme operates within Bitcoin’s most stringent legacy scripting constraints (201 opcodes, 10,000 bytes scripting limit) and is available to anyone willing to pay roughly $75 to $150 for cloud GPU computing and send transactions directly to miners via a service like MARA’s Slipstream.
StarkWare has been at the center of Bitcoin’s quantum defense efforts. Co-founder Eli Ben Sasson argued that Bitcoin must start responding to quantum threats now.
structure
A standard Bitcoin transaction uses a digital signature scheme called ECDSA to prove ownership of funds. A quantum computer running Scholl’s algorithm could reverse engineer that signature process to derive the private key from the public key and steal the coins.
QSB replaces the security model. Instead of relying on the mathematical hardness of an elliptic curve, which a quantum computer can break, it relies on the hardness of an inverse hash function, which a quantum computer cannot break. This scheme forces would-be spenders to solve computationally expensive hashing puzzles that tie transactions to a specific set of parameters. Attempting to modify the transaction invalidates the puzzle solution and forces the attacker to start over.
As a result, the security for Scholl’s algorithm is approximately 118 bits. In contrast, the security of a standard Bitcoin transaction in a post-quantum world is virtually zero.
early
The project is still in progress. The GPU pinning search, the first of three phases required to build quantum-secure transactions, was successfully tested and found valid results after approximately 6 hours on eight Nvidia RTX PRO 6000 GPUs. However, digest searches and on-chain broadcasts are not yet complete end-to-end.
There are also practical constraints. The transaction exceeds the default relay policy limits and must be sent directly to the miner. The lock script must be placed as bare output because it exceeds P2SH’s 520-byte redemption script limit.
Still, this release shows that without waiting for the community to agree to a soft fork, it is possible to achieve some degree of quantum resistance with Bitcoin today if someone is willing to shoulder the cost.
This article was written with the help of AI Workflow. All of our stories are hand-picked, edited and fact-checked by humans.
