Is Bitcoin Quantum Safe Already? - Avihu Levy QBC Ep. 05

Bitcoin's quantum problem has always come with an assumption attached: fixing it means changing Bitcoin. What if it doesn't? In the [Nth] episode of The Quantum Bitcoin Podcast, Bitcoin historian Pete Rizzo and co-host Nathan Jeffay put that question to Avihu Levy, Chief Product Officer at StarkWare, who spent his evenings, weekends and holidays proving that a quantum-safe Bitcoin transaction can be built today, inside the rules Bitcoin already has, with no soft fork and no consensus battle.Episode 5 is the one that doesn't ask permission: how Quantum Safe Bitcoin shifts security from elliptic curves to hash pre-images without touching a line of consensus code, why the trick lives entirely inside legacy script and its 201-opcode, 10,000-byte constraints, how revealing eight secrets out of a hundred makes a forged signature worthless to the attacker who forged it, and what that costs in transaction size, in dollars per spend, and in transactions that no ordinary node will relay. It covers the limitations Avihu puts up front himself, what a wallet would have to hold, and how Robin Linus's Binohash became the missing piece after a commenter dismissed it as useless. It closes with the two things the mechanism cannot solve: what happens when a working workaround becomes an argument against ever fixing the protocol properly, and what Bitcoin does about the coins that will never move.The Quantum Bitcoin Podcast is a series examining the quantum threat to Bitcoin, designed to be watched in sequence. Each episode opens with a discussion between the hosts, presents extended interviews with expert guests on a single key question, and closes with a recap of how the evidence has changed their thinking.Links referenced:https://starkware.co/blog/quantum-safe-bitcoin-transactions-without-softforks/https://github.com/avihu28/Quantum-Safe-Bitcoin-Transactionshttps://bitcoinops.org/https://delvingbitcoin.org/https://github.com/bitcoin/bips/blob/master/bip-0032.mediawikihttps://github.com/bitcoin/bips/blob/master/bip-0340.mediawikihttps://github.com/bitcoin/bips/blob/master/bip-0341.mediawikiCryptography and historyhttps://en.wikipedia.org/wiki/Shor%27s_algorithmhttps://en.wikipedia.org/wiki/Grover%27s_algorithmhttps://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithmhttps://en.wikipedia.org/wiki/Lamport_signaturehttps://en.wikipedia.org/wiki/RIPEMDhttps://en.wikipedia.org/wiki/SHA-2https://en.wikipedia.org/wiki/Preimage_attackPresented in partnership with Starkware.CHAPTERS00:00 Cold open01:00 Introducing Avihu Levy03:34 How QSB came about08:19 The limitations up front11:47 Signatures without a protocol change16:07 Robin Linus and Binohash19:00 A quantum safe spend23:43 What wallets would have to hold26:38 Size, cost and non-standard transactions30:03 What QSB does to the debate32:55 When a workaround becomes an excuse35:05 The field of proposals37:13 The coins that never move41:57 Why he is optimistic45:03 Rizzo and Nathan wrap upGUESTSAvihu Levy is Chief Product Officer at StarkWare. In April 2026 he published "Quantum-Safe Bitcoin Transactions Without Softforks," introducing Quantum Safe Bitcoin (QSB), a scheme that makes Bitcoin transactions resistant to an adversary running Shor's algorithm without any change to the protocol. QSB operates entirely within existing legacy script constraints and builds on Binohash (Linus, 2026), replacing reliance on elliptic curve security with hash pre-image assumptions. The paper and script generation tools are published open source alongside it.FOLLOWThe Quantum Bitcoin Podcast: https://www.youtube.com/@QuantumBitcoinPodcastPete Rizzo: https://x.com/pete_rizzo_Starkware: https://starkware.co/Avihu Levy: https://x.com/avihu28New episodes release weekly. Subscribe to follow the full series.