Researchers have cut the estimated computing cost of a specialized quantum-safe Bitcoin transaction by 82% to $59, according to data from the Quantum-Safe Bitcoin Optimization Challenge.
Improvements in graphics processing software reduced the projected expense from approximately $320 in August to $67 in September and $59 as of October 13. The public competition, organized by StarkWare, Yukon Research, and Eigen Labs, used AI-assisted coding tools to accelerate computational searches. The latest benchmark recorded more than 1 billion verified candidates per second on an Nvidia RTX 4090 GPU, up from approximately 146 million initially.
StarkWare said the improvements make its proposed emergency protection method considerably cheaper to prepare, with researchers now targeting a computing cost below $10.
Quantum computing threat intensifies security race
The development builds on research by StarkWare's Avihu Levy, who demonstrated in August that Bitcoin could support a quantum-resistant spending arrangement under its existing consensus rules. Known as Quantum-Safe Bitcoin (QSB), the method uses hash-based cryptography and a computational puzzle to secure specially prepared Bitcoin holdings against attacks on conventional digital signatures.
The approach lets holders perform required calculations off-chain before spending their coins, potentially offering protection while developers work on broader changes to Bitcoin's cryptographic infrastructure.
That research has gained urgency as advances in quantum computing challenge previous estimates of how much computing power attackers would need to compromise cryptocurrency security. In March, Google Quantum AI reported that future quantum computers could break the elliptic-curve cryptography used by Bitcoin with substantially fewer resources than previously estimated. Its researchers calculated that certain attacks could theoretically complete in minutes using fewer than 500,000 physical qubits under specified hardware assumptions, roughly a 20-fold reduction from earlier estimates.
Substantial exposure on the network
According to a study by Glassnode, approximately 6.04 million BTC—representing 30.2% of Bitcoin's issued supply at the time—had public keys already visible on-chain. The figure included 1.92 million BTC exposed through their underlying address structures and another 4.12 million BTC exposed through practices such as address reuse and previous spending activity. A sufficiently powerful quantum attacker could theoretically derive private keys from those exposed public keys and gain control of the associated coins.
Limitations and next steps
The $59 figure remains a hardware-dependent estimate based on simulated GPU workloads rather than a completed production transaction. Bitcoin network fees are separate, and some computing stages still rely on provisional assumptions.
QSB protects only eligible coins whose conventional public keys remain hidden until they are moved into specially constructed outputs. That requirement leaves already-exposed holdings vulnerable if a capable quantum attacker emerges before owners can complete a secure migration.
Although QSB transactions comply with Bitcoin's consensus rules, ordinary network relay policies reject them, requiring direct submission to miners willing to process them. StarkWare continues to favor a broader Bitcoin protocol upgrade for long-term protection. Researchers must demonstrate the latest computing savings in complete transactions and establish dependable miner access before QSB can become a practical fallback for holders.
