A researcher from the StarkWare team has unveiled a new method enabling quantum-resistant Bitcoin transactions without the need for any changes to the underlying protocol. This groundbreaking solution, however, comes with a significant cost—up to $200 per transaction—limiting its use primarily to critical situations rather than serving as a routine alternative.
The technical approach behind Quantum Safe Bitcoin
Avihu Levy, a StarkWare researcher, outlined a novel scheme this week called Quantum Safe Bitcoin (QSB) in a newly published paper. The main objective of QSB is to allow Bitcoin users to carry out quantum-secure transactions, all without modifying the existing protocol. Central to QSB’s design is the replacement of signature-based security, which currently underpins Bitcoin transactions, with hash-based proofs that do not rely on the same vulnerabilities.
Traditionally, digital signatures authenticate that a transaction comes from the rightful owner by leveraging their private key. Bitcoin utilizes the ECDSA signature algorithm—a method that is secure against conventional computers but, in theory, could be cracked by sufficiently powerful quantum computers. With quantum computing power, it is possible to derive private keys from public keys, putting user funds at risk.
QSB reimagines transaction security by using hash-based proofs, essentially producing a mathematical fingerprint that resists forgery. The unique summaries created under this system are extremely difficult to break, whether using today’s or tomorrow’s most advanced computers, thus mitigating risks posed by future quantum threats.
Challenges and costs
A key advantage of QSB is its compatibility with Bitcoin’s current consensus rules. There is no need for protocol upgrades, miner signaling, or special activation processes. This distinguishes QSB from long-term proposals like BIP-360, which have yet to be included in Bitcoin Core and would require substantial network-wide changes if adopted.
Still, QSB brings notable financial and practical hurdles. Each transaction requires intensive GPU-based computations in the cloud, sifting through billions of possibilities before reaching a suitable candidate. Estimates suggest transaction costs using QSB range from $75 to $200, a significant leap from the current average Bitcoin transaction fee of about $0.33.
Instead of submitting QSB transactions through the typical blockchain pathways, users must directly contact miners willing to process such requests. At this time, integrating QSB with scalable, low-cost solutions like the Lightning Network appears unfeasible. Producing these transactions also demands specialized technical knowledge and additional hardware resources.
Levy emphasizes that this method is not intended as a permanent fix but rather as a “last resort” if the Bitcoin network faces a genuine quantum computing threat. For long-term protection, proposals like BIP-360—which would bring more permanent, protocol-level resistance—are expected to be more suitable, though their implementation could take years.
The activation timeline for BIP-360 remains uncertain. Historically, Bitcoin network upgrades and technical proposals have required substantial discussion and consensus, often stretching over long periods. Similarly, most experts agree that quantum computers capable of threatening Bitcoin’s cryptography are unlikely to emerge in the short term.
Despite higher costs and complexity, QSB provides an alternative path for users determined to shield their assets from potential quantum attacks while adhering strictly to the existing protocol rules.
