Bitcoin achieved a milestone this week with the completion of its first known quantum-resistant transaction. On August 27, StarkWare and MARA Foundation teams announced the accomplishment, which demonstrates a potential path forward for securing the network against quantum computing threats.
Eli Ben-Sasson, CEO of StarkWare, characterized the development as significant for Bitcoin's post-quantum readiness. The transaction showcased both that quantum-safe transfers on Bitcoin are feasible and that solutions exist to make the network quantum-ready.
Current Bitcoin Quantum Vulnerabilities
Most modern Bitcoin wallet addresses, including Pay-to-Public-Key-Hash (P2PKH) and Native SegWit (P2WPKH), are quantum resistant while unspent. These addresses display only a hash that conceals the public key on the blockchain. However, when funds are spent, the actual key becomes visible on the network, potentially exposing these addresses to theft if quantum computers become sufficiently advanced.
The Quantum-Safe Solution
StarkWare developed a scheme called quantum-safe Bitcoin (QSB) transactions that improves security without requiring a softfork. The approach aims to provide quantum-resistant protection during the spending process while the network explores protocol-level upgrades.
The transaction was made possible through MARA's private mempool called Slipstream. Isabela Foxen, head of the MARA Foundation, noted that while private mempools may not represent a long-term solution for Bitcoin quantum resistance, they can support interim measures during the development of consensus changes.
Industry Proposals and Market Outlook
Blockstream, led by Adam Back, released a Bitcoin Improvement Proposal (BIP) for a post-quantum signature scheme named SHRINCS, describing it as a strong option among current alternatives for a network-wide upgrade.
Any eventual protocol-level upgrade will require extensive discussion and refinement before adoption. Currently, market participants are pricing only a 5% probability that such an upgrade will occur this year.
