The researcher proposed a transaction scheme that achieves quantum resistance for Bitcoin without the need for forking.

Deep Tide TechFlow News, April 12, According to Decrypt, StarkWare researcher Avihu Mordechai Levy recently published a paper proposing a transaction scheme called “Quantum-Safe Bitcoin (QSB)” that can enable Bitcoin transactions to resist quantum computing attacks without modifying the Bitcoin protocol, soft forks, or network upgrades.

The scheme replaces the existing elliptic curve signatures (ECDSA) with hash-based cryptography and Lamport signatures, which are believed to withstand attacks from quantum computers running Shor’s algorithm. The core of the scheme is an off-chain cryptographic puzzle that must be solved before broadcasting the transaction. The paper estimates that finding a valid solution requires approximately 70 trillion attempts but can be completed with consumer-grade hardware like GPUs at a cost of a few hundred dollars, with the computational results submitted to the network along with the transaction. Additionally, the scheme introduces a “transaction pinning” mechanism, requiring any attacker attempting to tamper with the transaction to redo the puzzle.

Levy admits that the scheme has several limitations: the off-chain computation costs and on-chain transaction size are both difficult to meet Bitcoin’s target throughput; the transaction creation process is more complex than standard operations and may be considered non-standard, requiring direct submission to mining pools rather than broadcasting through the public mempool; meanwhile, Grover’s algorithm can still provide quadratic speedup for quantum attackers. Levy positions this scheme as a “last resort” rather than a scalable, permanent solution, emphasizing the ongoing need for protocol-layer research and implementation of more comprehensive quantum-resistant solutions.

Currently, the quantum threat to Bitcoin remains theoretical, but companies like Google and Cloudflare have begun preparations and set a target to complete quantum migration by 2029.