Arthur Hayes' Family Office Bets On Bitcoin Privacy – Caps Grants At $400,000

Silent Payments' Bitcoin Core integration is awaiting review of the cryptography library.

• Arthur Hayes' family office announced that the firm was financially supporting four open-source Bitcoin developers.
• Half of grantees work full-time on privacy protocols, said Maelstrom, with a focus on Payjoin and Silent Payments, making transactions harder to track.
• Bull Bitcoin and Cake Wallet now support Payjoin, with five additional wallet integrations pending.

Arthur Hayes’ family office is putting money behind one of Bitcoin’s most contentious and closely watched areas: privacy. In its first annual Bitcoin Grant Program report, Maelstrom, the family office of BitMEX co-founder Arthur Hayes, revealed that two of the four open-source developers it currently funds are working full-time on privacy-focused technologies designed to make Bitcoin transactions harder to trace. 

It said on Wednesday that "Bitcoin is about game theory and asymmetry" - and that even minority adoption of privacy tools can improve the network for everyone.

Grant stacking is limited to $400,000 per year, and four open-source Bitcoin developers receive monthly Bitcoin payments under 12-month contracts. Two of the four work full-time on privacy protocols and two on Bitcoin Core, the network's standard software. Since October 2024, the program has funded five developers, four of whom are active.

Payjoin And Silent Payments Aim To Reduce Blockchain Surveillance 

Two grantees, Benalleng and Macgyver, build tools that make Bitcoin transactions harder to trace.

Surveillance firms rely on a simple assumption that all coins entering a transaction belong to the sender. Payjoin, Benalleng's project, breaks that by letting the recipient quietly add their own coins too, scrambling the money trail. It is already live in Bull Bitcoin and Cake Wallet, with five more integrations underway.

Silent Payments, Macgyver's focus, tackles address re-use — receiving repeated payments at one address makes your whole history public. It lets users share a single payment code while every payment lands at a fresh, unlinkable address. Several wallets now support it, and a new GPU-based tool, Frigate, has cut payment-scanning time from minutes to seconds.

Bitcoin Core Integration Remains Key Milestone 

The missing piece is Bitcoin Core, the software that runs the network. A Coldcard pull request became the first hardware-device implementation of Silent Payments, but Core integration is stalled on a cryptographic library still under review — deliberately slow, since bugs there can put real money at risk.

The other two grantees work directly on that core software: Rkrux, one of its busiest code reviewers, with 1,155 review comments in 2025, and Stratospher, fixing subtle bugs in the code that keeps the network in sync.

Why Network Privacy Matters For Bitcoin

Because Bitcoin's ledger is public, every transaction is permanently visible, and surveillance firms can trace funds and link addresses to real identities, which is what Payjoin and Silent Payments are built to prevent. 

The same transparency leaves older addresses with their public keys exposed on-chain, which makes them vulnerable to quantum-computing attacks that could derive private keys from those public keys. For instance, Satoshi Nakamoto, the Bitcoin creator, is estimated to hold 1.1 million BTC, a stash worth roughly $67 billion at the current market price.

Bitcoin’s price was trading at $60,974, down over 2% during the past 24 hours. On Stocktwits, the retail sentiment around BTC remained in the ‘bearish’ zone, while chatter around it stayed in the ‘high’ levels over the past day.

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