Bitcoin’s First Quantum-Safe Transaction Has Been Confirmed on Mainnet, No Protocol Change Required
A 10,000 Satoshi Transaction That Made History
On August 26, 2026, a 10,000 satoshi output moved through Bitcoin’s mainnet in block 964,199 using a method that no quantum computer, no matter how powerful, could reverse. The transaction used Quantum Safe Bitcoin, or QSB, a construction developed by StarkWare researcher Avihu Levy that replaces the elliptic-curve cryptography Bitcoin normally relies on with hash-based security derived from the preimage resistance of RIPEMD-160. No soft fork was needed. No hard fork. No protocol change of any kind. The transaction worked within Bitcoin’s existing consensus rules exactly as they stand today.
The significance is not the amount. It is the proof. Bitcoin’s standard signatures use elliptic-curve cryptography, which a sufficiently powerful quantum computer running Shor’s algorithm could eventually crack, deriving private keys from exposed public keys and stealing funds. QSB sidesteps that vulnerability entirely by anchoring its security to hash functions rather than elliptic curves, offering an estimated 118 bits of second-preimage resistance against a quantum attacker.
How It Works and What It Costs
QSB is not a simple upgrade that every wallet can switch on overnight. Each quantum-safe spend requires approximately $75 to $150 in off-chain cloud GPU computation before broadcast. The transaction format is non-standard, meaning it does not pass through Bitcoin’s normal mempool relay. Levy submitted the transaction directly to MARA’s Slipstream service, a mining pool that accepts non-standard transactions. This means QSB currently works only for holders willing to pay the computational cost and who have access to a cooperating miner.
The method protects legacy Bitcoin outputs but does not currently secure Taproot addresses, Lightning Network channels, or coins whose public keys have already been exposed on the blockchain. Approximately 7 million BTC fall into that last category, already visible on-chain and beyond QSB’s protection without a broader protocol-level solution.
What This Means for Bitcoin Holders
The transaction does not make Bitcoin quantum-safe overnight. What it does is prove that a working escape route exists within Bitcoin’s current rules, available right now to holders who want to move funds into quantum-resistant storage before the threat materialises. StarkWare continues to advocate for a protocol-level soft fork as the long-term solution, but the mainnet demonstration shows that Bitcoin does not have to wait for consensus on an upgrade before individual holders can begin protecting their coins. The quantum clock is ticking. As of August 26, 2026, Bitcoin has its first confirmed proof that it can outrun it.
The method protects legacy Bitcoin outputs but does not currently secure Taproot addresses, Lightning Network channels, or coins whose public keys have already been exposed on the blockchain. Approximately 7 million BTC fall into that last category, already visible on-chain and beyond QSB’s protection without a broader protocol-level solution.