First Quantum-Resistant Bitcoin Transaction Confirmed on Mainnet Without Protocol Change

Bitcoin got its first known quantum-resistant transaction on mainnet today, mined through MARA’s private Slipstream mempool using a method called Quantum Safe Bitcoin, built by StarkWare’s Avihu Levy.

It closes a real gap in how Bitcoin protects funds in transit, without asking the network to change a single consensus rule, though even the people behind it call it a stopgap rather than a fix.

How Quantum-Safe Bitcoin Closes the Mempool Gap Bitcoin held behind a hashed address, the P2PKH format most wallets use, is already considered safe from quantum attacks. The problem shows up the moment someone spends it.

Sending Bitcoin means revealing the wallet’s public key, and that key sits exposed in the mempool for roughly the ten minutes it takes to confirm, exactly the window a quantum computer could exploit.