Bitcoin Optech newsletter #409 is here: - describes a draft BIP to replace the testnet4 test network with a successor - Optech Newsletter #409 Podcast bitcoinops.org/en/newsletter…

Pyth (@pythcoiner) and Ademan (@Ademan555) joined Optech to discuss Newsletter #408: News ● A post-quantum path for BIP324 (37:15) ● Discussion of QR signing payloads for miniscript wallets (1:27) Changing consensus ● CTV-only vault proof of concept (13:08) ● Post-quantum Lightning discussion (43:41) ● Quantum attack game theory (47:24) ● BIP54 64-byte transactions and potential legitimate uses (49:15) Releases and release candidates ● Core Lightning 26.06 (1:11:15) Notable code and documentation changes ● Bitcoin Core #35269 (1:15:42) ● Bitcoin Core #34644 (1:20:45) ● Bitcoin Core #34198 (1:22:21) ● LND #10813 (1:26:32) ● Rust Bitcoin #6250 (1:28:05) ● BOLTs #1338 (1:36:06) ● BOLTs #1326 (1:37:23)

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Today we’re publishing Maelstrom's Bitcoin Grant Program Annual Report, for the period ending June 2026. The report covers the technical work of the four Maelstrom funded open source developers, working to improve Bitcoin, with respect to scalability, robustness and privacy.

bitcoinfuzz is a project to differentially fuzz test Bitcoin protocol implementations. It throws quasi-random inputs at different Bitcoin implementations (& libraries) at the same time to see where there are differences in behavior. Its finding real bugs. From @brrrunog & team:

sedited (@sedited_), Bitcoin Kernel developer and Bitcoin Core maintainer, blog post on validation logic in Bitcoin Core: "Block validation logic in Bitcoin Core is surprisingly complex. After more than a decade of engineering towards improving performance, Bitcoin Core has accumulated many caching layers, sub-steps, and optimizations before the node even calls the script interpreter. In the following, I’ll describe in broad strokes what these are, first roughly describing what validation is done in which order, then explaining why it was implemented in the way it is and the tradeoffs involved"... thecharlatan.ch/Validation/

Brink has always funded remote engineers, since our inception. Our London office is there for those who want an in-person space to collaborate, but it's always been optional. In fact, most of the engineers we've funded over the years have worked remotely. The mix shifts over time. Right now it's 5 in office and 4 remote. Wherever you are and whatever lets you do your best work on Bitcoin is what we're here to support.

With all of the exploits in DeFi, Zcash, and all of the other insanely complex crypto systems we are reminded again that Bitcoin’s simplicity is its biggest feature.

Making BIP324 quantum resistant QR-based signing for miniscript wallets CTV vault proof of concept Post-quantum Lightning Quantum attack game theory 64-byte transactions and potential uses

A more verbose explanation regarding my grant from @bitcoinbrink conduition.io/bitcoin/my-fir…

More on conduition's post-quantum plans:

Chandra Pratap joined Optech to discuss Newsletter #407: News ● Core Lightning assertion DoS disclosure (0:47) ● Bitcoin Core developer meeting transcripts (14:34) Releases and release candidates ● Eclair v0.14.0 (20:30) ● Core Lightning 26.06rc2 (23:01) Notable code and documentation changes ● Bitcoin Core #33966 (24:14) ● Bitcoin Core #34917 (28:04) ● Bitcoin Core #35017 (30:52) ● BIPs #1944 (35:25) ● BIPs #2108 (36:14) ● Eclair #3192 (39:28) ● LDK #4584 (40:28) ● LDK #4628 (41:27) ● LND #10552 (43:35) ● LND #10820 (48:52)

3,272 applicants. 50 selected contributors from 7 countries. 26 bitcoin orgs. One very exciting summer ahead. Summer of Bitcoin 2026 is officially underway. Meet the next generation of Bitcoin builders: blog.summerofbitcoin.org/sum…

Last week was the Lightning Dev Summit in Vienna, full of great people & talents, where we discussed the future of Lightning at the protocol level Here are my personal takeaways: 1/N 🧵

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I'm hyped to announce that I am Brink's first-ever grantee to focus on Bitcoin's post-quantum crypto R&D 🎉🤓 brink.dev/blog/2026/06/01/co… This funding will help me focus full-time as I collaborate with @blksresearch to draft a balanced, efficient, and secure PQ signature upgrade.

Brink’s first grant for post-quantum, part of our focus on potential threats that could affect Bitcoin’s long-term security. I've considered for some time how Brink can thoughtfully participate with quantum work. I've always been impressed with @conduition_io's work and blog and it seems like a great fit.

We are excited to announce that conduition (@conduition_io) has joined Brink as cryptographic engineer working on post-quantum cryptographic research and implementation!

Apple on their open-source tools for formal verification "Deploying this new generation of algorithms at scale across all Apple platforms requires high assurance, so we developed rigorous new formal verification methods to prove the mathematical correctness of our implementation." "The practical considerations are more complicated. Regardless of how it’s applied, formal verification requires a tremendous investment of time and deep expertise." security.apple.com/blog/form…

Brink's pilot of a internship grant program was a success. Always good to get more eyes and hands on important testing infrastructure.