Quantum-safe Bitcoin spending drops 82% in cost as researchers battle to protect 6 million exposed coins
Computing costs for quantum-resistant Bitcoin moves fall sharply
Researchers working on a specialized Bitcoin protection method have cut the estimated computing cost from around $320 down to $59, a drop of 82%. The cost reduction comes from a GPU optimization challenge organized by StarkWare, Yukon Research, and Eigen Labs. The method, known as Quantum-Safe Bitcoin or QSB, lets users move Bitcoin in a way that protects it against future quantum computers without requiring changes to the Bitcoin network itself. About 6.04 million BTC, representing roughly 30% of Bitcoin's supply, have public keys already visible on the blockchain, leaving them potentially exposed if quantum computers become powerful enough to break Bitcoin's current cryptography. The $59 estimate is still theoretical. It is based on simulated GPU workloads, not a completed live transaction. Bitcoin network fees are separate from the computing cost. Some computing steps still rely on provisional assumptions rather than tested results.
Key numbers in the optimization effort
- Cost estimate dropped from $320 in August to $67 in September to $59 as of October 13.
- GPU search speed reached over 1 billion verified candidates per second on an Nvidia RTX 4090, up from about 146 million at the start.
- About 6.04 million BTC have exposed public keys on-chain.
- 1.92 million BTC are exposed through their underlying address structures.
- 4.12 million BTC are exposed through address reuse and previous spending activity.
- StarkWare says researchers are now targeting a computing cost below $10.
What the challenge organizers say
The competition used AI-assisted coding tools to speed up the computational searches needed for the transactions. The goal is to make the emergency protection method affordable enough for wide use. StarkWare researcher Avihu Levy first demonstrated in August that Bitcoin could support a quantum-resistant spending arrangement under its existing rules. The approach relies on hash-based cryptography and a computational puzzle to secure specially prepared Bitcoin holdings against attacks on conventional digital signatures. The method allows holders to do the required calculations off-chain before spending their coins, offering a potential bridge while developers work on broader changes to Bitcoin's cryptographic infrastructure.
The quantum threat driving the urgency
In March, Google Quantum AI reported that future quantum computers could break the elliptic-curve cryptography used by Bitcoin using far fewer resources than previously thought. Researchers calculated that certain attacks could theoretically complete in minutes with fewer than 500,000 physical qubits under specific hardware assumptions, about a 20-fold reduction from earlier estimates. Such machines do not yet exist at public scale, but the findings have increased pressure on blockchain developers to prepare before quantum attacks become practical. European police agency Europol has urged crypto wallets to upgrade now, warning that migration could take years.
What still needs to happen
QSB only protects coins whose conventional public keys remain hidden until they are moved into specially constructed outputs. Coins with already-exposed public keys cannot use this method for protection going forward. The approach also requires miners willing to process the nonstandard Bitcoin transactions it creates. Whether QSB becomes a widely adopted interim solution or a permanent fixture depends on whether these technical and network adoption hurdles can be cleared in time.
Why this matters
The cost drop makes a practical emergency defense more affordable, but the window to protect vulnerable Bitcoin holdings is narrowing as quantum computing research advances. The 6 million exposed coins represent a real attack surface if quantum computers reach the necessary capability.
Sources
Newisty Editorial Team covers technology, cryptocurrency, digital products, online platforms, developer tools and the wider digital economy. Our content is researched from official sources, company announcements, public documentation, market data and other primary or reputable sources. Articles are reviewed and edited before publication for clarity, accuracy and useful context.
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