Bitcoin News: StarkWare Brings Quantum-Resistant Bitcoin Transfer to Mainnet

StarkWare said researcher Avihu Levy has tested an experimental quantum-resistant Bitcoin transaction on mainnet. The transaction reportedly spent a 10,000-satoshi output in block 964,199 without making changes to Bitcoin’s consensus rules.

The company called the transaction the first of its type. MARA Pool mined the block after receiving the transaction directly through its Slipstream service because its nonstandard format prevented regular Bitcoin nodes from relaying it through the public mempool.

Nathan Jeffay, a StarkWare spokesperson, estimated the computing expense at roughly $150 to $200. StarkWare said the process took several hours, showing that its approach can provide quantum-resistant protection for an individual Bitcoin output under existing rules, although it currently requires significant computing and operational resources.

How StarkWare’s Quantum-Resistant Bitcoin Transaction Works

Levy proposed the Quantum-Safe Bitcoin (QSB) system in April. It combines hash-based one-time signatures with computational searches that connect spending authorization to a specific transaction. The mechanism is designed to prevent unauthorized spending even if sufficiently powerful quantum computers eventually break Bitcoin’s elliptic-curve cryptography.

Google researchers estimated in March that a capable quantum computer could theoretically derive a Bitcoin private key within nine to 12 minutes after the associated public key is exposed. Google said this could potentially give attackers enough time to replace a transaction while it is still awaiting confirmation.

Levy’s April proposal estimated that generating a QSB transaction would require around $75 to $150 in GPU computation. StarkWare’s completed transaction put the actual cost at approximately $150 to $200.

QSB targets individual Bitcoin transactions instead of replacing the network’s cryptographic system. It enables coins to be moved into specially protected outputs without changing Bitcoin’s protocol. However, it cannot secure coins whose public keys were already exposed before migration, potentially leaving those funds vulnerable while the keys remain visible.

Another limitation is the transaction’s nonstandard status under Bitcoin Core’s default relay policy. Ordinary nodes will not broadcast it before confirmation, so users must submit it directly to a cooperating miner through a service such as MARA’s Slipstream. This requires prepared transactions as well as access to a participating miner.

StarkWare CEO Eli Ben-Sasson said QSB could function as a safety layer while the Bitcoin community develops broader protocol-level defenses. The demonstration provides a way to introduce quantum-resistant spending without altering Bitcoin’s underlying cryptographic architecture.

Developers are also examining BIP-360, a proposed soft fork that would introduce Pay-to-Merkle-Root outputs and remove Taproot’s quantum-vulnerable key-path spending. Implementing that proposal would require coordination across the Bitcoin network and formal activation.

Unlike BIP-360, QSB does not depend on a protocol upgrade. The mainnet test demonstrates that Bitcoin’s existing consensus rules can accommodate a form of quantum-resistant spending, although wider adoption will depend on addressing the method’s computational and operational limitations.