A Bitcoin researcher has proposed a method that could make Bitcoin transactions quantum-safe without requiring a protocol upgrade or soft fork.
In a paper published Thursday, StarkWare chief product officer Avihu Levy introduced a scheme called Quantum Safe Bitcoin (QSB), which he claims would remain secure even against a large-scale quantum computer running Shor’s algorithm.
Levy said the approach works entirely within Bitcoin’s existing legacy script constraints and does not require any changes to the protocol. However, he noted that the method is computationally expensive and likely impractical for everyday transactions.
The proposal comes as the Bitcoin community remains divided over how to address quantum computing risks, with QSB positioned as a potential interim safeguard while longer-term solutions are developed.
At the core of the scheme is a replacement of the traditional signature verification process with a hash-based “signature puzzle.” Instead of relying on elliptic curve cryptography—which could be broken by quantum computers—the spender must find an input whose hash output coincidentally matches a valid ECDSA signature structure, a process that requires brute-force effort that even quantum systems cannot efficiently bypass.
The proposal comes with notable limitations. It is estimated to cost between $75 and $150 per transaction in GPU compute, making it significantly more expensive and more complex than standard Bitcoin transfers. As a result, it would likely only be suitable for high-value transactions rather than everyday use.
StarkWare CEO Eli Ben-Sasson called the idea “huge,” arguing that it effectively makes Bitcoin quantum-safe today.
However, Bitcoin ESG specialist Daniel Batten described that claim as “an overstatement,” pointing out that the approach does not address exposed public keys or dormant wallets.
Batten highlighted concerns around an estimated 1.7 million BTC stored in early P2PK addresses, which could potentially be vulnerable to quantum attacks.
This issue has sparked ongoing debate within the Bitcoin community over how to handle at-risk dormant coins, with differing views ranging from leaving the system unchanged, to freezing or burning vulnerable funds, or implementing a protocol upgrade with quantum-resistant signatures.
The researchers themselves acknowledged that the scheme is intended only as a last-resort measure, noting that transactions are non-standard, costs do not scale well for general use, and key systems like the Lightning Network are not supported.
They ultimately concluded that protocol-level upgrades remain the preferred long-term solution.
“While this article describes a solution that works today for quantum-safe Bitcoin transactions, it should be treated as a last-resort measure.”
In March, Google published a paper that unsettled parts of the Bitcoin community, suggesting that a quantum computer might be able to break Bitcoin’s cryptography using far fewer resources than previously estimated.
Meanwhile, on Wednesday, Lightning Labs CTO Olaoluwa Osuntokun introduced a quantum “escape hatch” prototype. The concept allows users to prove ownership of a Bitcoin wallet derived from an original seed phrase without exposing the phrase itself, potentially offering an alternative method of authorization in a post-quantum scenario.
