StarkWare says a Bitcoin transaction built with its Quantum-Safe Bitcoin, or QSB, method has been mined on mainnet. The company describes it as the first mainnet transaction of its kind.
It is designed to withstand an adversary using a working quantum computer. The demonstration required no change to Bitcoin’s consensus rules, according to StarkWare’s announcement.
StarkWare Researcher Executes First Quantum-Safe Bitcoin Transaction on Mainnet StarkWare researcher Avihu Levy’s Quantum-Safe Bitcoin (QSB) scheme has completed its first confirmed transaction on the Bitcoin mainnet, demonstrating a way to protect transactions from… pic.twitter.com/ZiCoQdMuhD
— Wu Blockchain (@WuBlockchain) August 27, 2026
QSB offers Bitcoin holders a way to move coins into storage protected by a hash-based construction rather than relying solely on elliptic-curve cryptography.
The method is not a conventional Bitcoin transfer: it requires substantial offchain computation and a direct route to a miner willing to accept a nonstandard transaction.
How QSB Protects a Bitcoin Quantum Spend Without a Consensus Change
Bitcoin signatures use elliptic-curve cryptography, which could be compromised by Shor’s algorithm on a powerful quantum computer, allowing an attacker to extract a private key from its public key.
Most Bitcoin addresses are hashes of public keys, keeping the public keys hidden until the addresses are spent. When a transaction is created, the public key is revealed, creating a window of opportunity for a quantum adversary to steal coins.
StarkWare’s QSB addresses this risk by adding a second layer of protection using hash functions, as Shor’s algorithm cannot break these.
The method involves signature grinding, allowing the sender to find a transaction hash that is also a valid Bitcoin signature before broadcasting. This shift means the output depends on hash difficulty rather than private key secrecy.
While QSB enhances security by moving coins to a hash-based output, it doesn’t make Bitcoin entirely quantum-safe. It can’t protect addresses where the public key has already been published, as an adversary could derive the private key before the transaction is sent.
Crypto Expert Report: What is the Best Meme Coin to Buy and Forget Until the Next Bullrun?
Why the Method Requires Computation and Miner Cooperation
StarkWare says the approach currently costs several hundred dollars in computation. Supplementary reporting by Cointelegraph said StarkWare described the process as taking hours of computation and estimated a completed-transaction cost of roughly $150 to $200.
QSB transactions also use nonstandard formats, meaning they do not travel through Bitcoin’s ordinary mempool under default relay policies. Instead, they need a direct submission path to a miner. StarkWare said MARA Slipstream provided that path for the demonstration.
The direct-miner requirement is a practical limitation. A holder seeking to move coins into the QSB construction must arrange for a miner to receive and include a nonstandard transaction rather than simply broadcast it through the standard peer-to-peer network. The method therefore remains distinct from an ordinary Bitcoin payment, which can be propagated through the usual mempool.
What the Mainnet Demonstration Changes
THis is definitely a move in the right direction. HOWEVER, QSB acts as an opt-in "parachute" for moving coins to quantum-resistant storage at a cost of ~$75-150 per transaction; it is NOT a network-wide fix and leaves most Bitcoin, including Taproot and Lightning, still… https://t.co/afgD2lbVCZ
— Digital Asset News (@NewsAsset) August 27, 2026
The demonstration establishes that a quantum-resistant spending construction can operate within Bitcoin’s existing rules without waiting for a protocol change. StarkWare nevertheless maintains that a soft fork is the better long-term approach to delivering broader quantum resistance across Bitcoin.
The method’s limitation is central to its use. QSB can protect coins before the relevant public key is exposed, but it cannot help an address whose public key was already visible before the transaction. In that situation, a future quantum adversary could already have access to the information needed to attempt private-key recovery.
StarkWare CEO Eli Ben-Sasson characterized the transaction as reassurance that Bitcoin holdings can be protected before a soft fork, while continuing to support a soft fork as the preferred long-term solution.
Crypto Expert Report: What Are the 10 Next Crypto to Explode in 2026?
The post StarkWare Mines Bitcoin Quantum-Safe Transaction on Mainnet appeared first on Tokenist.