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The first post-quantum Bitcoin transaction was broadcast this week. At Bitcoin Asia, the Sharknet Foundation explained how it was done.
Should fund managers dealing in Bitcoin be worried about the threat of quantum computing?
The short answer is yes — but there’s time to prepare and solutions are already being found.
One of them? Post-quantum Bitcoin transactions on the mainnet. And the first one happened this week thanks to the Starknet Foundation.
JUST IN: The first post-quantum resistant Bitcoin transaction was mined today."It required no soft forks. It required no hard forks. It required no core protocol upgrades. And it's live today." pic.twitter.com/YyZbHhm8HI
Speaking at Bitcoin Asia in Hong Kong on Thursday, Damian Chen, VP of growth at the Starknet Foundation, demonstrated how funds vulnerable to future quantum attacks can be secured without requiring a network-wide fork, thanks to the company’s latest solution.
“This is a monumental moment,” Chen said. “This is the first post-quantum-resistant Bitcoin transaction on bitcoin mainnet today. It required no soft forks; it required no hard forks; it required no core protocol upgrades, and it’s live today.”
The transaction happened using a method created by StarkWare researcher Avihu Levy. It works like this: Bitcoin transactions sit briefly in a public queue before confirmation. During that window, they expose cryptographic material that a sufficiently powerful quantum computer could use to forge a signature and steal the funds before the transaction is confirmed.
But rather than accepting the first valid signature, his method generates millions of signature candidates until it finds one with a specific structural property that doesn’t expose that vulnerable material while waiting in the mempool.
This “signature grinding” is deliberately computationally expensive — a single transaction takes hours to produce — but that cost is what makes it resistant to quantum shortcuts.
Touting Quantum safe Bitcoin transactions — dubbed “QSB” — to institutions, Chen said that even if attackers have a fund’s private keys, they couldn’t make a fraudulent transfer.
“QSB introduces a new hash authorization, and so an attacker with a sufficiently capable computer, even if they have your exposed public key, even if they derive your private key from your public key, even if they try to use that to authorize a spend to move your coins out of your wallet, those things are not enough for them to do so,” he said.
