Bitcoin Safe: hardware-only cold storage

Rob is the creator of Kyoto, an implementation of compact block filters that makes it easier for developers to build more private bitcoin wallets. Andreas is the creator of Bitcoin Safe, an app designed to make it easier to use hardware wallets securely.

Andreas on Nostr: https://primal.net/p/nprofile1qqsqd0y6klqxew4glwggn63jvumrgprnl32tw7hpuzfhv6msgf7y3agm756qu
Bitcoin Safe on Nostr: https://primal.net/p/nprofile1qqsyz7tjgwuarktk88qvlnkzue3ja52c3e64s7pcdwj52egphdfll0cq9934g
Bitcoin Safe on X: https://x.com/BitcoinSafeOrg
Kyoto on Github: https://github.com/rustaceanrob/kyoto
2140: https://2140.dev

EPISODE: 185
BLOCK: 926163
PRICE: 1099 sats per dollar

(00:03:04) Bitcoin Dev Kit

(00:04:39) Andreas (Bitcoin Safe) and Rob (Kyoto)

(00:05:58) What is BDK? Goals, safety, and language bindings

(00:09:27) Why BDK matters for UX, testing, and reliability

(00:09:50) Kyoto origin story and compact block filters vision

(00:13:21) Privacy model: servers vs. compact block filters

(00:19:39) Do compact block filters work on mobile? Performance tradeoffs

(00:23:55) Kyoto as a Rust reference client for BIP157/158

(00:24:35) Bitcoin Safe overview: desktop cold storage with hardware signers

(00:25:40) Using compact block filters in Bitcoin Safe: initial sync vs. daily speed

(00:28:27) Why connect your own node and peer pools for CBF

(00:33:14) Design choice: hardware-only wallets and setup wizard

(00:36:29) Differentiating from Sparrow: private sync and Nostr-based multisig coordination

(00:39:08) Will Sparrow adopt compact block filters? Considerations and UX

(00:48:49) Developer ecosystems: 2140, OpenSats, and in-person collaboration

(00:50:38) Making CBF the default: UX, education, and recovery flow

(00:52:56) Electrum server defaults and operational notes

(00:53:50) Birth heights, segwit/taproot start points, and future optimizations

(00:56:17) Address reuse, scanning guarantees, and performance benchmarks

(01:00:13) Bandwidth vs. compute: where the real bottlenecks are

(01:00:19) Closing discussion, calls to action, and advice for new devs