A new research proposal claims that Bitcoin transactions can be made resistant to quantum attacks without changing the underlying rules of the network, a goal that has drawn attention as concerns grow about future crypto risks.
In a research paper published on April 9, StarkWare’s Avihu Levy said shown Quantum Secure Bitcoin Transactions Without Soft Forks offers a scheme called Quantum Secure Bitcoin, or QSB. The design aims to protect transactions from… Threats Quantum computers introduce it while maintaining compatibility with the current Bitcoin protocol.
The proposal targets a known security vulnerability in Bitcoin’s current design. Standard transactions are based on ECDSA signatures via secp256k1 curve. In theory, a sufficiently powerful quantum computer running Shor’s algorithm could break this system by solving discrete logarithms, which would allow attackers to forge signatures and spend money.
QSB replaces reliance on elliptic curve safety with segmentation-based assumptions. Instead of trusting ECDSA, the scheme uses it as a verification mechanism while converting security to pre-image hash resistance. This approach is derived from Previous work known as Pinohashwhich integrates one-time signature schemes into Bitcoin Script.
At the heart of QSB is the hash-to-signature puzzle. The system hashes the public key derived from the transaction using RIPEMD-160 and treats the output as a candidate ECDSA signature. Only a small fraction of random hashes meet the strict formatting rules required for valid signatures, creating a proof-of-work requirement. The paper estimates the probability of success at about one in 70.4 trillion attempts.
Bitcoin is resistant to quantum attacks
Since the puzzle relies on segmentation properties rather than the rigidity of the ellipse curve, it remains resistant to Shor’s algorithm. A quantum attacker would only get a quadratic speedup from Grover’s algorithm, leaving large security margins. The paper estimates about 118 bits of pre-image resistance under the Shor threat model.
The build works within Bitcoin’s current scripting limits, including a maximum of 201 opcodes and a maximum script size of 10,000 bytes. It uses legacy script structures and avoids any need for consensus changes or soft forks, a feature that may appeal to developers who are concerned about protocol fragmentation.
The transaction process unfolds in three stages, the proposal claims. First, the “fix” phase searches for transaction parameters that produce valid output from hash to signature, and associates the transaction with a fixed structure. Next, two rounds of summaries select subsets of the included signatures to generate additional evidence associated with the transaction hash. Finally, the transaction is bundled with all required raw images and verification data.
Design offers trade-offs. QSB transactions exceed the limits of the standard relay policy, which means they will not spread across the network under default settings. Instead, they require direct provision to miners through services like Slipstream. Scripts also consume a lot of space and computational resources.
Despite these limitations, the cost of creating a valid transaction appears affordable. The paper estimates total computing overhead at between $75 and $150 using cloud GPUs, scaling the workload across parallel machines. Early testing indicates successful puzzle solutions after several hours using multiple GPUs.
The project remains incomplete. While the paper and script generation tools are being finalized, parts of the pipeline, including full transaction aggregation and streaming, are not yet on-chain.
However, the proposal adds to a growing body of research exploring how Bitcoin can adapt to current conditions The future is with quantum computing. By avoiding protocol changes, QSB offers a single path that relies on existing rules rather than agreed-upon upgrades, a trend that may shape more debate about network security in the long term.
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