Bitcoin successfully executed its first experimental quantum-safe transaction using existing protocol rules, without requiring a network upgrade.
Tech & Launches ·
StarkWare, the blockchain infrastructure company behind Starknet, announced that a quantum-resistant Bitcoin transaction was mined on mainnet using existing protocol rules and without requiring a network upgrade. The transaction employed Quantum-Safe Bitcoin (QSB), a method developed by StarkWare researcher Avihu Levy, which adds hash-based cryptographic protection alongside Bitcoin's standard elliptic-curve security. According to StarkWare CEO Eli Ben-Sasson, the transaction demonstrates that individual Bitcoin holders can now move coins into storage resistant to quantum computers before any network-wide defense is implemented.
Bitcoin's current encryption scheme relies on elliptic-curve cryptography, which theoretical quantum computers running Shor's algorithm could theoretically compromise to extract private keys. The QSB method works by applying "signature grinding"—computational work performed off-chain to generate a transaction hash Bitcoin will accept as a valid signature. While StarkWare views a soft fork as the preferred long-term defense, QSB provides immediate protection for new transactions without waiting for consensus changes across the network.
The experiment carries important limitations. As many as 7 million Bitcoin may remain vulnerable due to exposed public keys and address reuse, which QSB cannot protect. Additionally, the current implementation requires transactions to be sent directly to miners. Ben-Sasson emphasized the measure addresses only part of the quantum threat and stressed that a serious network-level soft fork remains necessary to truly secure Bitcoin against quantum risks.