StarkWare Sends First Quantum-Resistant Bitcoin Transaction in Block 964,199
August 27, 2026
Bitcoin Quietly Crosses a Quantum Milestone
While traders watched Bitcoin wrestle with the $80,000 level this week, something arguably more important happened in the background. StarkWare, the company best known for its Ethereum scaling technology, confirmed the first quantum-resistant Bitcoin transaction ever recorded on the network’s mainnet. The transaction was small, just 10,000 satoshis, worth roughly $8 at current prices. Its significance is not the amount. It is proof that Bitcoin, in its current form and without any change to its rules, can already produce a payment that a quantum computer could not forge. For years, the quantum threat has hung over crypto as a distant but uncomfortable question. This week, one researcher showed a possible answer already exists.What Actually Happened in Block 964,199
The transaction was built by Avihu Levy, a StarkWare researcher, using a method the company calls QuantumnSafe Bitcoin (QSB). It was confirmed on Wednesday in Bitcoin block 964,199, according to Cointelegraph. Because the transaction uses a nonstandard format, ordinary Bitcoin nodes refuse to relay it across the network. Levy had to submit it directly to a miner, and MARA Pool picked it up through its Slipstream service, which specializes in processing unusual transactions. That detail matters. The technique works today, but it does not yet travel through Bitcoin’s normal plumbing. It is a proof of concept, not a product.
Why Quantum Computers Scare Bitcoin Holders
To understand why this experiment matters, it helps to know how Bitcoin payments work. Every wallet has two linked pieces: a public key, which works like an account number others can see, and a private key, which works like the only signature that can approve spending from that account. Today’s computers cannot work backward from a public key to find the private key. A sufficiently powerful quantum computer could. Google researchers have estimated that such a machine could, in theory, derive a private key within 9 to 12 minutes of the public key becoming visible on the network. Here is the uncomfortable part: every time someone spends from a Bitcoin address, the public key is exposed while the transaction is pending confirmation. That waiting window is exactly when a future quantum attacker could strike, forge a signature, and redirect the funds. Anyone tracking the Bitcoin price has, until now, simply had to trust that the hardware capable of doing so does not yet exist.How the Quantum-Safe Method Works
Levy’s approach flips Bitcoin’s existing machinery into a shield. Instead of accepting the first valid signature a wallet produces, the QSB method brute-forces millions of candidate signatures and continues searching until it finds one whose mathematical structure does not expose the vulnerable public key material, according to The Block. The method combines hash-based one-time signatures with computational searches that lock an authorization to one specific transaction. The security rests on hash functions, which quantum computers are far less effective against than the elliptic-curve cryptography protecting standard Bitcoin payments. Crucially, none of this required a fork. Bitcoin’s consensus rules accepted the transaction as perfectly valid.The Catch: Hours of Computing and a $200 Bill
Quantum resistance does not come cheap. Producing a single QSB spend currently requires hours of computation and costs in the low hundreds of dollars, with estimates around $150 to $200 per transaction in cloud computing power. There is also the relay problem. Until node software treats these transactions as standard, every QSB payment needs a direct line to a cooperative miner. That makes the method impractical for everyday use across crypto market prices and retail wallets in its current form. StarkWare itself frames the technique as a bridge rather than a destination. CEO Eli Ben-Sasson described the experiment as proof that “there are lifeboats,” while stating plainly that “a soft fork should happen, and I believe it will.”Will Bitcoin Upgrade Before Quantum Computers Arrive?
The timing question remains open. Nobody knows when, or whether, a quantum computer capable of breaking Bitcoin’s cryptography will exist. Estimates from researchers range from a decade away to never. What has changed is the shape of the debate. Until now, the assumption was that Bitcoin would need a contentious protocol upgrade before any quantum protection could exist. This experiment suggests holders may have an emergency option even if the network moves slowly, though the cost and complexity would need to fall dramatically before it could protect ordinary users. If quantum hardware progresses faster than expected, demand for these techniques could accelerate, and the pressure for a formal soft fork may build alongside it.A Security Debate That Just Became Practical
The milestone lands in a market that has been focused almost entirely on price, with Bitcoin’s push past $80,000 this week dominating headlines. Quantum security is the opposite kind of story: slow, structural, and easy to ignore until it suddenly is not. Block 964,199 will not move markets. What it does is convert a theoretical argument into a working demonstration, and that changes the burden of proof. The question is no longer whether Bitcoin can defend itself against quantum computers without tearing up its rulebook. It is how quickly the network chooses to make that defense practical for everyone.
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Madiha Riaz
Madiha is a seasoned researcher in cryptocurrency, blockchain, and emerging Web3 technologies. With a background in organic chemistry and a sharp analytical mindset, she brings scientific depth to decentralized innovation. Since discovering crypto in 2017 and investing in 2018, she’s been uncovering and sharing deep insights into how blockchain is redefining the digital asset landscape.
