Maelstrom, the family office of BitMEX co-founder Arthur Hayes, has released its first annual report for the Bitcoin Grant Program. The document covers a 20-month span starting October 2024 and details work by four active developers — Rkrux, Stratospher, Benalleng, and Macgyver — who are funded through 12-month contracts paid monthly in Bitcoin. Each developer receives up to $400,000 per year, fully paid by Maelstrom.
Four developers, two focus areas
Two grantees work on Bitcoin Core itself; the other two focus on Bitcoin privacy infrastructure. Since the program launched, five developers have been supported in total. The review committee consists of Hayes and Jonathan Bier.
Rkrux: 1,155 review comments and counting
Rkrux has been a grantee since October 2024. In 2025, they made 1,155 review comments across more than 200 pull requests, ranking 11th among the most active commenters on the Bitcoin Core codebase. In the first five months of 2026, Rkrux added over 400 more PR comments. Their work includes MuSig2 — a protocol that makes multisig indistinguishable from single-sig — and deprecating legacy wallets in favor of descriptor-based wallets.
Stratospher catches a bug, pushes privacy
Stratospher, funded since November 2025, discovered and fixed an undefined behavior bug in Bitcoin Core's FindMostWorkChain function. They also contributed to removing the BLOCK_FAILED_CHILD flag and worked on DLEQ proofs in libsecp256k1 for Silent Payments. Stratospher presented at the Africa Bitcoin Conference on open source development and privacy.
Payjoin integrations grow
Benalleng, funded since June 2025, works full-time on Payjoin, a protocol that breaks the heuristic that all transaction inputs belong to the same party. The Payjoin API has been integrated into Bull Bitcoin and Cake Wallet, with five or more additional wallet integrations in progress. Bindings for Python, Javascript, Dart, and CSharp have been released.
Pushing Silent Payments forward
Macgyver, also funded since June 2025, focuses on Silent Payments (BIP-375), which allows payments to a static address without address reuse. Wallet support now includes send/receive on Blindbit-Desktop, Cake Wallet, and Dana Wallet; Sparrow Wallet and Nunchuk support sending. A draft implementation for Bitcoin Core is on hold pending a libsecp256k1 module dependency. Macgyver formalized the Silent Payments roadmap, produced BIP-375 test vectors, proposed the first working hardware signer implementation for Coldcard, and organizes monthly working group meetups.
The grant program continues to fund developers on a rolling basis, with all funding from a single source.
