Bitcoin Mainnet Sees First Quantum-Resistant Transaction Test by StarkWare
In a groundbreaking experiment, StarkWare successfully executed a quantum-resistant Bitcoin transaction without requiring a network fork, though the process demanded approximately $200 in costs and necessitated direct submission to miners.
In what the company characterizes as a pioneering achievement, StarkWare researcher Avihu Levy has successfully executed an experimental quantum-resistant transaction on Bitcoin's mainnet network.
The transaction received confirmation on Wednesday within Bitcoin block 964,199, as reported by StarkWare. Blockchain records reveal that the transaction consumed a 10,000-satoshi output secured by Levy's Quantum Safe Bitcoin (QSB) methodology, with the block being mined by MARA Pool following submission via its Slipstream service.
According to Levy's published paper and corresponding code repository, QSB merges hash-based one-time signatures with computational searches that link an authorization to a particular transaction. This design aims to thwart forgery attempts even in scenarios where quantum computers successfully compromise the elliptic-curve cryptography currently employed by Bitcoin.
The practical test advances Levy's April theoretical proposal into a real-world onchain proof of concept, illustrating that Bitcoin's current consensus mechanisms can support this form of quantum-resistant spending without necessitating protocol modifications.
Quantum-resistant Bitcoin method remains costly
Back in March, researchers from Google provided estimates suggesting that a quantum computer with adequate capabilities could theoretically calculate a Bitcoin private key within nine to 12 minutes following public key exposure. According to Google's assessment, this vulnerability could enable an attacker to substitute a pending transaction while it awaits confirmation on Bitcoin's network.
Subsequently in April, Levy unveiled QSB, projecting that producing such a transaction would demand GPU computation costs ranging from $75 to $150. He characterized the solution as an emergency fallback option instead of a substitute for protocol-level security measures.
Nathan Jeffay, a spokesperson for StarkWare, informed Cointelegraph that the executed transaction incurred costs in the "low hundreds of dollars," with estimates placing the figure somewhere between $150 and $200. According to StarkWare's announcement, the computational process consumed multiple hours.
Levy's code repository further indicates that QSB transactions fall into the nonstandard category under Bitcoin Core's default relay policies. Consequently, as StarkWare explained, standard nodes would refuse to propagate the transaction prior to confirmation, making direct submission through MARA's Slipstream service a necessity.
QSB functions on individual Bitcoin transactions rather than implementing a network-wide cryptography upgrade. "A soft fork should happen, and I believe it will," stated StarkWare CEO Eli Ben-Sasson, further noting that QSB serves as a protective safeguard during the development phase of protocol-level defenses.
In parallel efforts, Bitcoin developers are evaluating alternative proposals such as BIP-360, a suggested soft fork that would establish a Pay-to-Merkle-Root output type while eliminating Taproot's quantum-susceptible key-path spend functionality.