Explore every episode of the podcast Quantum Bitcoin Countdown

What actually happens to Bitcoin the day a quantum computer arrives? In the third episode of The Quantum Bitcoin Podcast, Bitcoin historian Pete Rizzo and co-host Nathan Jeffay put that question to Jameson Lopp, the Bitcoin security researcher who has spent the past year writing the attack scenarios out in full and who authored BIP-361, the first Bitcoin Improvement Proposal of his 14 years in Bitcoin.

Episode three maps what the attack actually looks like: why a quantum attacker works in silence rather than in public, how roughly six blocks of block space could sweep 95% of the most valuable exposed addresses before anyone knows it is happening, what Lopp heard when he asked quantum computing companies directly whether they would take vulnerable coins, why address reuse has already exposed around 30% of all Bitcoin, and why he expects roughly 2.6 million coins to never migrate at all. It closes with the uncomfortable part: what deprecating elliptic curve cryptography would mean for people who cannot move their coins, why Lopp thinks the real constraint is not the computer but the decade Bitcoin needs to agree on anything, and what he actually wants to see happen on Q-Day.

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.

Presented in partnership with Starkware.

CHAPTERS
00:00 Cold open
01:24 What this episode covers
02:08 Rizzo and Nathan set up the question
06:40 Meet the expert: Jameson Lopp
07:38 Why quantum is half a dozen problems at once
10:35 Q-Day and the real target: Bitcoin's signatures
14:16 What a quantum attacker does first
15:58 Six blocks: how the sweep plays out
17:44 Why nobody announces a working quantum computer
20:19 The board meeting: asking the quantum companies directly
22:47 Enigma, salvage law, and the softer target
25:04 Why Lopp refuses to predict a date
27:50 Safe until you spend: the mempool attack
29:44 Address reuse and the 30% already exposed
31:38 The migration math: 17.5 million move, 2.6 million don't
33:41 Why the upgrade takes a decade
36:19 Why Lopp rejects the collective action framing
38:24 A systemic threat, not an individual one
43:49 Deprecating elliptic curve cryptography
46:38 Rescue paths and why nobody gets rug pulled
49:06 Setting the record straight on Satoshi's coins
53:12 Every other chain has this problem
56:40 What Lopp wants to happen on Q-Day
57:30 Recap: what we learned about the attack scenarios

GUESTS
Jameson Lopp is a Bitcoin security researcher and co-founder of Casa, with 14 years in Bitcoin and a decade working in Bitcoin security, previously at BitGo. He is the author of BIP-361, which proposes deprecating elliptic curve cryptography on a fixed timeline to force migration before a quantum attacker arrives, and he publishes his research at lopp.net.

FOLLOW
The Quantum Bitcoin Podcast: https://www.youtube.com/@QuantumBitcoinPodcast
Pete Rizzo: https://x.com/pete_rizzo_
Starkware: https://starkware.co/
Jameson Lopp: https://x.com/lopp

New episodes release weekly. Subscribe to follow the full series.

How far away is a quantum computer that can break Bitcoin? In the second episode of The Quantum Bitcoin Podcast, Bitcoin historian Pete Rizzo and co-host Nathan Jeffay put the series' central question to Ethan Heilman, the Cloudflare researcher and Bitcoin cryptographer who co-authored BIP-360, the proposal that put quantum security on Bitcoin's agenda.

Episode two maps the threat itself: how Heilman went from dismissing quantum computers as science fiction to treating them as a this-decade problem, why he refuses to name a date, what the idea of Q-Day gets wrong, which parts of Bitcoin are actually exposed and which survive untouched, and why the NSA, the banks, and nearly half of web traffic have already gone post-quantum while Bitcoin debates. It closes with the warning signs to watch for, and why whoever breaks the cryptography first may choose to stay silent.

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.

Presented in partnership with Starkware.

CHAPTERS
00:00 Cold open
01:00 What this episode covers
01:30 Rizzo and Nathan set up the question
05:49 Meet the expert: Ethan Heilman
06:16 From sci-fi to serious: how Heilman changed his mind
09:11 Why no one can give you a date
12:40 The state of quantum hardware in 2026
17:11 Q-Day: why there is no single moment
20:29 What post-quantum cryptography actually is
22:29 Why mining and SHA-256 survive
26:37 The real target: Bitcoin's signatures
29:46 Is there any science behind 2030?
31:22 Who has already migrated: the NSA, the banks, the web
33:22 Store now, break later
34:31 Why an attacker would listen, not steal
39:15 Choosing Bitcoin's post-quantum signatures
48:28 Tsunami warnings and the final signal
57:00 Recap: what we learned about the quantum timeline

GUESTS
Ethan Heilman is a researcher at Cloudflare and a Bitcoin developer and cryptographer whose work goes back to the earliest days of the project. He is the creator of TumbleBit and a co-author of BIP-360, the proposal that put post-quantum security on Bitcoin's development agenda.

FOLLOW
The Quantum Bitcoin Podcast: https://www.youtube.com/@QuantumBitcoinPodcast
Pete Rizzo: https://x.com/pete_rizzo_
Starkware: https://starkware.co/
Ethan Heilman: https://x.com/Ethan_Heilman

New episodes release weekly. Subscribe to follow the full series.

What is a quantum computer, and does it pose a genuine threat to Bitcoin? In the first episode of The Quantum Bitcoin Podcast, Bitcoin historian Pete Rizzo and co-host Nathan Jeffay begin a structured inquiry into the question hanging over the industry: whether, when, and how quantum computing could break the cryptography that secures Bitcoin.Episode one establishes the foundations:nwhat separates a quantum computer from every machine that came before it: qubits, superposition, and the capacity to represent an entire field of possible states at once.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.Presented in partnership with Starkware.CHAPTERS00:00 Cold open00:46 What this episode covers01:10 Introducing the series and co-host Nathan05:46 Meet the experts: Rob Hamilton and Brandon Black06:38 Classical vs quantum: what a qubit actually is08:06 Why quantum computing threatens Bitcoin's cryptography09:39 Shor's algorithm: what it can and cannot break11:53 Inside the machines: superconducting, neutral atom, trapped ion, photonic15:03 Theory vs practice: the factoring gap18:09 Q-Day: definitions and disputed timelines21:57 Could governments be hiding a quantum breakthrough?24:04 What a quantum attack on Bitcoin would actually require25:56 Post-quantum cryptography: hash-based signatures and BIP-36029:33 Recap: what we learned about quantum computersGUESTSRob Hamilton is the co-founder of AnchorWatch, a Bitcoin custody and insurance company focused on the long-term security of keys and coins.Brandon Black is a Bitcoin educator who has spent years making the protocol's most difficult concepts accessible.FOLLOWThe Quantum Bitcoin Podcast: https://www.youtube.com/@QuantumBitcoinPodcastPete Rizzo: https://x.com/pete_rizzo_Starkware: https://starkware.co/Rob Hamilton: https://x.com/Rob1HamBrandon Black: https://x.com/reardencodeNew episodes release weekly. Subscribe to follow the full series.

Can Bitcoin's signatures actually be replaced, and what does the replacement cost? In the [Nth] episode of The Quantum Bitcoin Podcast, Bitcoin historian Pete Rizzo and co-host Nathan Jeffay put that question to Jonas Nick, Blockstream's Director of Research, who has spent the past year and a half building the smallest post-quantum signature scheme anyone has proposed for Bitcoin and who maintained Bitcoin's secp256k1 library for over seven years before that.

Links referenced:https://blockstream.com/quantum/https://blog.blockstream.com/op_checkshrincs-a-hash-based-signature-opcode-for-post-quantum-bitcoin/https://eprint.iacr.org/2025/2203https://delvingbitcoin.org/t/shrincs-post-quantum-signatures-for-bitcoin/https://blog.blockstream.com/searching-for-shrincs-parameters/https://blog.blockstream.com/blockstream-quarterly-update-q1-2026/https://blog.blockstream.com/blockstream-quarterly-update-q2-2026/https://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/SPHINCS%2Bhttps://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithmhttps://en.wikipedia.org/wiki/Schnorr_signaturehttps://en.wikipedia.org/wiki/Merkle_signature_schemehttps://en.wikipedia.org/wiki/Lamport_signaturehttps://en.wikipedia.org/wiki/Lattice-based_cryptographyhttps://en.wikipedia.org/wiki/SHA-2Presented in partnership with Starkware.CHAPTERS00:00 Meet the expert: Jonas Nick00:32 A year and a half inside the problem01:59 It isn't only the signatures. Lightning too.03:40 The assumption everything rests on04:47 What cryptographers stopped researching05:27 Why a plan is needed regardless of timing06:16 If Bitcoin does nothing: every coin, gone07:13 Why this needs a consensus change08:39 The people who say it will never happen10:01 Bitcoin as a social construct11:24 The government's post-quantum billions13:12 Why NIST's use case doesn't transfer14:42 Why hash-based is the conservative bet15:00 100x larger signatures15:37 Seven transactions per second becomes half of one16:52 There is no free lunch17:03 What breaks: BIP-32, silent payments, MuSig, FROST18:01 Verification time and who stops running nodes18:56 Signing time and the hardware wallet problem20:50 No reinsurance22:42 No silver bullet23:06 SHRINCS and the statefulness trade-off23:19 Five to ten times larger, seven down to three25:06 Who actually pays for this26:04 Why he won't bundle a block size increase27:05 Four megabytes was never the right number29:35 What SHRINCS actually is35:38 Why Bitcoin's usage pattern makes this work37:36 Already running on Liquid38:38 What Liquid doesn't protect39:47 The next step is a BIP41:23 Nobody knows what rough consensus means43:21 What changed in the last six months44:17 Where to follow the discussionGUESTSJonas Nick is Director of Research at Blockstream, where he leads the post-quantum signature work. With cryptographer Mikhail Kudinov he designed SHRINCS, a hash-based signature scheme producing 324-byte signatures whose security rests entirely on SHA-256, and SHRIMPS, its multi-device counterpart. In May 2026 he published OP_CHECKSHRINCS, a proposed Bitcoin opcode that would verify those signatures through an extension of the Taproot tree. FOLLOWThe Quantum Bitcoin Podcast: https://www.youtube.com/@QuantumBitcoinPodcastPete Rizzo: https://x.com/pete_rizzo_Starkware: https://starkware.co/Jonas Nick: https://x.com/n1cklerNew episodes release weekly. Subscribe to follow the full series.