Avihu Levy, a researcher at StarkWare, has successfully executed the first Bitcoin transaction specifically engineered to withstand attacks from future quantum computers. This experimental transaction was processed on the Bitcoin mainnet using a hashing-based signature system that requires no changes to the network's consensus rules.
Avihu Levy's QSB transaction bypasses the need for a soft fork
The transaction utilized a system called Quantum-Safe Bitcoin (QSB), which was developed by StarkWare researcher Avihu Levy. According to the report, QSB replaces the standard elliptic-curve digital signatures—which are theoretically vulnerable to quantum decryption—with hashing, a cryptographic method considered far more resilient to quantum-level threats.
Because QSB operates within the existing transaction rules of the Bitcoin network, it does not require a soft fork or any modification to the underlying software. This allows users to create a "quantum-resistant escape hatch" immediately, providing a way to secure funds without waiting for a global network upgrade that may take years to negotiate.
The few hundred dollar GPU cost per QSB transaction
While the technical achievement is significant, the practical application of Quantum-Safe Bitcoin is currently limited by extreme computational overhead. As the report says, creating these quantum-resistant transactions requires substantial off-chain computation, with Avihu Levy's original paper estimating the GPU cost at a few hundred dollars per transaction.
This cost structure stands in stark contrast to the nominal fees typically associated with standard Bitcoin transfers. Consequently, the StarkWare researcher presented this method as a last-resort security measure for high-value holdings rather than a viable replacement for everyday payments.
Why 6.04 million BTC remain exposed to Shor's algorithm
The urgency for such a tool stems from the fact that a sufficiently powerful quantum computer running Shor's algorithm could derive a private key from an exposed public key. This would allow an attacker to seize funds from any address where the public key is known to the network.
The scale of this vulnerability is immense. Data from analytics firm Glassnode indicates that roughly 6.04 million BTC—approximately 30.2% of the total issued supply—have public keys already exposed on-chain. At a valuation of $80,000 per coin, this represents roughly $483 billion in assets that could be targeted. This includes the early coins held by Bitcoin creator Satoshi Nakamoto, which represent a massive potential prize for the first entity to develop a cryptographically relevant quantum machine.
The $15 million security pledge from BlackRock and Coinbase
The instittional sector is already moving to hedge against this systemic risk. A consortium including BlackRock, Coinbase, Fidelity Digital Assets, Galaxy, Blockstream, and Strategy has pledged $15 million over three years to fund Bitcoin security research, with a primary focus on post-quantum cryptography.
This financial commitment suggests that while the "Q-day" threat may not be imminent, the potential for a total collapse of trust in Bitcoin's ownership model is a risk that the world's largest asset managers cannot ignore.
Matt Corallo's push for a pre-Q-day migration mechanism
Despite the success of the QSB test, the Bitcoin community remains divided on the permanent solution. Early developer Matt Corallo has argued that the priority should be increasing the number of coins secured before a quantum computer exists , thereby reducing the need for an emergency fork to burn vulnerable coins.
However,critical questions remain regarding the fate of inactive wallets. It is still undecided whether coins that owners fail to migrate should be frozen forever or if they should be left open for a quantum-equipped entity to claim. The source reports that the industry has yet to reach a consensus on whether to implement a soft fork that disables vulnerable spending paths once the threat becomes critical.
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