Built on OrangeCheck
Real projects that use the protocol, the SDK, or the sign-in-with-Bitcoin flow in production. Curated — the bar is a working integration, not a tagline. Shipped something? Tell us via /contact and we'll add it.
Seal a payload so only the holder of a specific Bitcoin address can open it. Recipients register X25519 device keys bound to their address via a BIP-322 signature, publish them to a Nostr kind-30078 directory, and any sender can encrypt a one-shot envelope (X25519 ECDH → HKDF-SHA256 → AES-256-GCM) that only those devices can unseal. No centralized key server, no account, no message broker — the Bitcoin address is the identity and Nostr is the directory.
- >>BIP-322 signatures to bind device keys to a Bitcoin address (the same signing primitive OrangeCheck attestations use)
- >>Nostr kind-30078 parameterized-replaceable events for device-key publication — same event kind OrangeCheck uses for attestations
- >>Optional OrangeCheck attestation on the sender side so recipients can gate inbound envelopes on proof of stake
OrangeCheck is an open protocol with an MIT-licensed reference stack. Anything that needs “this user has stake” or “this public key is tied to a Bitcoin address” can build on it without asking permission.
Start with the quickstart for a 30-second integration, or the how-it-works page for the full mental model. When you ship, reach out via /contact and we'll add your project to this page.