Please report security issues privately through GitHub private vulnerability reporting rather than opening a public issue. Include reproduction steps and the affected surface (PWA, Cloudflare Functions backend, or the native Android/iOS app — the native client lives in the android-ios-app directory, which accepts reports the same way).

We aim to acknowledge reports promptly and to credit reporters in release notes unless they prefer otherwise.

• Private messages and group chats are end-to-end encrypted (NIP-17/NIP-44/ NIP-59); relays and the D1 storage layer only ever hold ciphertext. Findings that break that property are the highest-value reports we can receive.
• Public channels (kinds 20000/23333) are intentionally unencrypted.
• The /api/proxy endpoint is intentionally unauthenticated (it exists to keep user IPs away from third-party servers); reports about its abuse potential should focus on bypasses of its SSRF, rate-limit, or content-type controls.

The Cloudflare Functions backend vendors its crypto primitives (secp256k1/schnorr, SHA-256/HMAC/HKDF, NIP-44) in functions/api/_shared.js rather than importing them, so dependency scanners will not flag upstream advisories automatically. Maintainers: when a security advisory lands for @noble/curves, @noble/hashes, or nostr-tools, re-vendor from the patched release. The provenance header at the top of _shared.js records what to compare against.