Bitcoin Could Be Quantum Safe Without a Soft Fork, Analyst Says

Highlights:

• Bitcoin transactions can be protected from quantum attacks using a method that works without network changes.
• The Bitcoin quantum safe model relies on costly computation, which limits its use to large and urgent transfers.
• The long-term protection of the network still depends on coordination between users and developers.

Bitcoin transactions may be safe from quantum risks without the need for a soft fork, according to a new proposal by StarkWare chief product officer Avihu Levy. Levy published the Quantum Safe Bitcoin, or QSB, proposal on Thursday and said it can secure transactions on the live network under existing rules. He designed the method to operate within Bitcoin’s legacy script constraints, so users do not need protocol changes to adopt it. The proposal also removes the need for miner signaling or a network activation process.

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👀 Le développeur Avihu Levy propose un nouveau modèle de transactions « quantum-safe » pour #Bitcoin, sans avoir besoin de recourir à un soft fork. pic.twitter.com/03SLpGMI8X

— Journal du Coin (@LeJournalDuCoin) April 10, 2026

Levy said the system allows users to protect transactions immediately while developers continue working on long-term solutions. He described the method as a last-resort option for high-value transfers and emergency scenarios. The proposal does not modify Bitcoin’s blockchain structure, but it changes how transactions prove ownership within the system. Therefore, it preserves compatibility with the current network while introducing a different verification process.

The design replaces the proof-of-work signature-size puzzle with a hash-to-sig puzzle. Under this model, the spender must search for an input whose hash output matches the structure of a valid ECDSA signature. Levy said this brute-force process avoids the shortcut a quantum computer could use against elliptic curve cryptography. He added that the method can remain secure even if a large-scale quantum computer runs Shor’s algorithm.

Bitcoin Quantum Safe Model Shifts Security Toward High-Cost Computation

Levy’s proposal introduces a Bitcoin quantum safe transaction model that replaces signature-based verification with a brute-force computation process. Bitcoin currently relies on ECDSA signatures, which use elliptic curve cryptography to prove wallet ownership. A sufficiently advanced quantum computer could derive private keys from public keys using Shor’s algorithm and compromise that system. Levy designed QSB to avoid that weakness by removing reliance on vulnerable cryptographic assumptions.

The QSB model requires the user to search through many inputs until one produces a hash that resembles a valid signature. This process depends on raw computation rather than mathematical shortcuts. As a result, quantum systems cannot speed up the attack in the same way they could break elliptic curve cryptography. According to Levy, this strategy will make sure that the transaction validation is secure in the presence of a quantum threat.

However, the added protection increases transaction costs. Levy estimated that each QSB transaction would require between $75 and $200 in GPU compute using cloud hardware. A standard Bitcoin transaction costs far less, which makes QSB impractical for routine payments. The system also shifts the workload away from the protocol because users must rely on external computing resources to generate valid transactions.

Meanwhile, a study published by the California Institute of Technology and Oratomic said useful quantum computers may require only 10,000 to 20,000 qubits to break BTC. The researchers said this lower threshold could make practical quantum systems possible before the end of this decade.

In a related development, Google published a paper that suggested a quantum computer could break Bitcoin cryptography with fewer resources than earlier estimates projected. The findings have increased focus on how the network can protect transactions before quantum systems become widely available.

🚨BREAKING: GOOGLE WARNS 6.9M BITCOIN WILL BE VULNERABLE WHEN QUANTUM COMPUTERS BECOME POWERFUL ENOUGH

A new Google Quantum AI whitepaper has identified approximately 6.9 million Bitcoin $BTC vulnerable to future quantum at-rest attacks.

Around 1.7 million BTC sits in old… pic.twitter.com/pCwKrhXL4e

— BSCN (@BSCNews) March 31, 2026

Industry Testing Expands as Proposal Remains a Last-Resort Measure

Levy said QSB should serve as a temporary option while developers pursue protocol-level upgrades for quantum resistance. He said the system provides immediate protection but does not address long-term scalability or usability. Developers continue to focus on changes that modify Bitcoin’s core cryptographic design.

Despite the looming quantum risk, some institutions have started implementing solutions to the risk. BTQ Technologies launched Bitcoin Quantum testnet v0.3.0 as a working implementation of BIP-360. The company said the test network runs on a separate blockchain so developers, miners, and researchers can study the upgrade without affecting the main Bitcoin network. This setup allows testing under controlled conditions before any potential deployment.

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