History of Metaprotocols on Bitcoin | ADAM KRELLENSTEIN Isabel Foxen Duke 2026-09-23 | History of Metaprotocols on Bitcoin | ADAM KRELLENSTEIN
Lose This Counter, Lose Your Bitcoin Isabel Foxen Duke 2026-08-30 | When your state counter is lost, SPHINCS+ is the backup. When SHRINCS falls back to the stateless side.
The Bitcoin Discount Debate Nobody Wants Isabel Foxen Duke 2026-08-29 | Post-quantum signatures are huge but cheap to verify, which is why the witness discount question keeps coming up — and why it gets controversial fast.
How Many Signatures Does SPHINCS Get You? Isabel Foxen Duke 2026-08-29 | 7. SHRINCS trades a little security budget for smaller signatures. You'd still need to sign for over 100 years to exhaust it.
The Signature Scheme With No Elliptic Curves Isabel Foxen Duke 2026-08-29 | SPHINCS explained — a stateless signature scheme built from one primitive, the hash function. The foundation SHRINCS is built on.
Bitcoin Relies on ONE Cryptographic Problem Isabel Foxen Duke 2026-08-28 | Why Bitcoin needs hash-based signatures even if quantum computers never arrive: all of Bitcoin's cryptography rests on a single problem.
Pay-to-Taproot V2 Is NOT Post-Quantum Isabel Foxen Duke 2026-08-27 | Conduition argues any post-quantum output type must be post-quantum, and Pay-to-Taproot V2 isn't. On P2MR, P2TR v2, and the Q-day timing problem.
Your Wallet Developer Could LOSE Your Bitcoin Isabel Foxen Duke 2026-08-27 | SHRINCS pairs a stateful signature scheme with a SPHINCS fallback — and puts state management on wallet developers.
A Cosmic Ray Could Steal Your Bitcoin Isabel Foxen Duke 2026-08-27 | Lose count of your signatures and you leak your private key. The stateful signature risk SHRINCS is designed around.
Bitcoins Leading Post-Quantum Signature Proposal | CONDUITION Isabel Foxen Duke 2026-08-26 | The first fully specified post-quantum signature scheme for Bitcoin has been proposed to the Bitcoin mailing list. The proposal introduces a full specification for “SHRINCS,” a hash-based signature scheme initially conceived by Jonas Nick and Mikhail Kudinov of Blockstream Research — with specification details added by new co-authors Conduition, Remix7531 and BIP 360 co-author Ethan Heilman. Today, I’m honored to share a full whiteboard explanation of the scheme by its co-author Conduition, as well as thorough discussion of the scheme’s key tradeoffs when compared to Bitcoin’s existing elliptic-curve signatures and competing post-quantum alternatives.In more detail, this interview includes: — A full whiteboard walkthrough of the scheme’s key components and its relationship to the NIST-standardized scheme SPHINCS+ — SHRINCs’ introduction of a compact stateful path - yes, I said stateful 🌶️— Whiteboard explanations of all relevant cryptographic subschemes, including FORS, WOTS+C, and XMSS— Thorough discussion of the scheme’s tradeoffs and implications for Bitcoin’s existing functionalityIf you have a vested interest in understanding what may be the future signature scheme protecting Bitcoin transactions in a post-quantum world, this episode is a must-watch.WARNING: this episode is fairly technical — don't beat yourself up if you don't catch everything, or need to watch it a few times to grok the details.This episode of Bitcoin Rails is brought to you by:LayerTwo Labs @LayerTwoLabs — developing research, software, and technologies for scaling Bitcoin via the integration of Drivechains (BIP 300/301)Hashi on @SuiNetwork — a primitive for executing Bitcoin DeFi transactions, without having to trust a federated bridge or other centralized entityBitBox @BitBoxSwiss — an open-source Bitcoin-only hardware wallet, with smooth UX and no compromises on security. Check out Bitbox [dot] swiss and use code BITCOINRAILS to get a discountTIMESTAMPS:00:00 — Intro01:26 — The SHRINCS BIP and how conduition got here05:26 — Building slhvk and joining the Blockstream working group08:34 — Why hash-based signatures, even without quantum14:08 — What SPHINCS is and what stateless really means18:45 — Losing count and why state is dangerous24:44 — SHRINCS and the stateless backupWHITEBOARD SESSION STARTS HERE:30:30 — Inside the SHRINCS public key34:39 — Winternitz signatures and hypertrees43:18 — Signature sizes and witness discount51:42 — Inside the stateful side and FXMSS1:01:25 — Where the stateful and stateless sides differ1:08:50 — UXMSS, BXMSS and getting wallet devs up to speed1:19:03 — FORS and the forest of random subsets1:34:24 — What Bitcoin gives up with hash-based signatures1:39:08 — Migration and where SHRINCS could be deployed
The Case For Lattice-Based Signatures in Bitcoin | CHARLES GUILLEMET Isabel Foxen Duke 2026-08-25 | To date, post-quantum Bitcoin discussions have largely centered on which digital signature schemes offer the strongest cryptographic security against a quantum adversary.But cryptographic assumptions are only one dimension of security.Different signature schemes introduce different implementation and operational risks. How should Bitcoin weigh cryptographic conservatism against the complexity required to deploy that cryptography safely?While hash-based signatures are often favored for their conservative assumptions, CTO of Ledger, Charles Guillemet argues that evaluating primitives in isolation can obscure consequential risks at the systems level.Stateful hash-based schemes, in particular, introduce state-management requirements where operational or user error can have catastrophic consequences —despite their conservative cryptographic foundations.In this interview, Charles and I examine the tradeoffs of hash-based signatures and his case for greater consideration of lattice-based alternatives, i.e. ML-DSA.A very juicy episode for anyone seriously assessing Bitcoin's post-quantum design landscape. This episode of Bitcoin Rails is brought to you by: LayerTwo Labs — developing research, software, and technologies for scaling Bitcoin via the integration of Drivechains (BIP 300/301) Hashi on Sui Network — a primitive for executing Bitcoin DeFi transactions, without having to trust a federated bridge or other centralized entity BitBox — an open-source Bitcoin-only hardware wallet, with smooth UX and no compromises on security. Check out Bitbox [dot] swiss and use code BITCOINRAILS to get a discount TIMESTAMPS:00:00 — Intro01:45 — How the quantum threat became real for Ledger09:06 — NIST influence and what Ledger built into its SDK21:25 — ML-DSA and why Falcon might not be the right choice25:33 — The problem with hash-based signatures31:38 — Stateful signatures and the throughput problem36:48 — Does user error outweigh the security difference?42:27 — Bitcoin post-quantum migration scenario45:15 — Maintaining multisig capabilities in a post-quantum world55:54 — NIST standardization process and the backdoor question1:01:06 — Trezor's approach and device authentication1:06:09 — Ledger’s approach to post-quantum signatures
Expecting Hardforks | PAUL SZTORC Isabel Foxen Duke 2026-08-07 | Paul Sztorc founder and CEO of LayerTwo Labs and author of Bitcoin Improvement Proposals 300 and 301 (Drivechains), has been one of Bitcoin's most persistent—and controversial—thinkers, advocating for merge-mined sidechains as a way to dramatically expand Bitcoin's functionality while preserving the security of the base layer.Following our previous episode introducing his proposed Bitcoin hard fork, eCash, we discuss how the project has evolved in recent months, what to expect when the fork launches on mainnet, and Paul's perspectives on today's Layer 2 landscape and the soon-to-activate BIP 110 soft fork.An entertaining, popcorn-style conversation with one of Bitcoin's most unconventional thinkers, this episode offers diverse—and at times irreverent—commentary on some of the most important technical debates shaping Bitcoin's future.This episode of Bitcoin Rails is brought to you by: LayerTwo Labs — developing research, software, and technologies for scaling Bitcoin via the integration of Drivechains (BIP 300/301) Hashi on Sui Network — a primitive for executing Bitcoin DeFi transactions, without having to trust a federated bridge or other centralized entity BitBox — an open-source Bitcoin-only hardware wallet, with smooth UX and no compromises on security. Check out Bitbox [dot] swiss and use code BITCOINRAILS to get a discountTIMESTAMPS: 00:00 — Intro00:16 — The Coldcard exploit09:37 — Can Bitcoin still soft fork?15:30 — Paul's hard fork26:12 — BIP 110's fork and the ghost of SegWit42:03 — How drivechains work and eCash53:00 — Quantum resistance and OP_CAT1:01:44 — Launching a drivechain and the OP_RETURN debate1:08:57 — The BIP 110 endgame: Udi trolling, hashrate, and Ocean1:13:54 — Why Stratum V2 is a bad idea1:20:33 — The decline of maximalism and the road ahead
The Future of Bitcoin Banking | ALEX LEISHMAN Isabel Foxen Duke 2026-07-28 | I first came across River during the 2020 bull market. At the time, it felt like one of the quieter players in the space—not as visible as Coinbase or Kraken, and less talked about than its Bitcoin-only competitor, Swan, which was dominating Bitcoin Twitter and investing heavily in KOL marketing at the time.My impression was that River had made a different bet: prioritizing product and security over rapid customer acquisition. In hindsight, that strategy paid off. As exchange and custody failures shook the industry during the 2022 bear market, River emerged as one of the most trusted names in Bitcoin.River CEO Alex Leishman joins me to discuss the technical, operational, and commercial decisions that have differentiated the company—and why many of those decisions have influenced the way the industry thinks about Bitcoin custody today.In more detail, we discuss:- Why River chose to remain Bitcoin-only despite the short-term revenue tradeoffs- The philosophical differences between Bitcoin banks and trader-driven crypto exchanges- Why River manages its own custody stack—and what actually matters when choosing a Bitcoin custodian- A recap of the industry's biggest custody failures: what went wrong and how to avoid repeating those mistakes- How Bitcoin custody has evolved over the past decade—and how it may need to evolve again in a post-quantum worldThis episode of Bitcoin Rails is brought to you by:LayerTwo Labs — developing research, software, and technologies for scaling Bitcoin via the integration of Drivechains (BIP 300/301) Hashi on Sui Network — a primitive for executing Bitcoin DeFi transactions, without having to trust a federated bridge or other centralized entity BitBox — an open-source Bitcoin-only hardware wallet, with smooth UX and no compromises on security. Check out Bitbox [dot] swiss and use code BITCOINRAILS to get a discount TIMESTAMPS: 00:00 — Intro00:57 — How Alex found Bitcoin09:16 — A monetary revolution11:35 — River as the bank of the future13:42 — Exchanges, hacks, and why trading isn't a lasting business18:02 — Who River is built for21:07 — Is non-Bitcoin crypto dying?25:35 — Store of value, spending, and the long-term fee question30:34 — Bitcoin banking and the role of fiat40:10 — Stablecoins as "KYC-free dollars" and Bitcoin lending45:44 — Inside River's custody: cold storage and security54:28 — Proof of reserves and accountability1:09:32 — How custody works: MPC vs multisig1:13:59 — How exchanges are handling quantum
