Bitcoin completes its first quantum-secure transaction

A quantum secure transaction was mined on the Bitcoin mainnet for the very first time.

The underlying effort, built around an April 2026 research paper by StarkWare’s Avihu Levy, turned Bitcoin’s scripting rules into a puzzle that Shor’s algorithm, the quantum method that can break elliptic curve cryptography, cannot solve.

What’s the scoop?

• The tip: Quantum-Safe Bitcoin (QSB) buries a second hash-based lock in the spending script. Rather than trusting the secret of a private key, it hashes a public key related to the transaction with RIPEMD-160 and checks if the result resembles a valid ECDSA signature (something only about 1 in 2^46 random keys will do). Finding this needle, without knowing a private key, is what authorizes the expenditure.
• Preliminary work: The design leverages Binohash by Robin Linus and a 2024 method by Ethan Heilman to smuggle Lamport signatures into Bitcoin Script without OP_CAT. QSB replaces Binohash’s ECDSA-dependent proof of work with one that relies solely on resistance to the hash pre-image, thereby sealing the exact gap that Shor’s algorithm would otherwise exploit.
• Mining: The completed transaction exceeds the standard limits of Bitcoin’s relay policy, so it couldn’t just wait in the memory pool. StarkWare’s Tomer Giladi led the implementation through to completion, and MARA’s Slipstream service (designed specifically for non-standard transactions like this) delivered it directly to a miner.
• The price to pay: Brute forcing the right transaction parameters required approximately $75 to $150 of GPU time, depending on the project specifications. GitHub repositorya cost which would decrease even more as more GPUs were launched into research.
• Not the last word: Levy himself downplayed this step, calling QSB “a research quirk and not a simple way for Bitcoin to become” quantum safe. StarkWare CEO Eli Ben-Sasson was more triumphant, writing that the result shows that “Bitcoin has no expiration date.”