security: scanner covers nsec/pepper classes; ignore bare-hex key files; PRIVACY.md

- tools/secret-scan.sh now also flags nsec1 Nostr secret keys and
  *_PEPPER/*_SALT/*INTEGRITY_SECRET hex assignments, the secret classes
  this backend actually handles (previously only PEM/seed shapes).
- .gitignore: *.hex + admin-key* so an operator running inside the
  checkout cannot commit the raw admin key (create-admin-wallet --out).
- PRIVACY.md pointing to the canonical smirk.cash/privacy, framed for
  self-hosting operators as independent data controllers.

.gitignore

@@ -11,6 +11,10 @@
 !.env.example
 *.key
 *.pem
+# Bare-hex secret files (e.g. `smirk-admin create-admin-wallet --out admin-key.hex`)
+# so an operator running inside the checkout cannot commit the raw admin key.
+*.hex
+admin-key*
 *.p12
 secrets/
 secret_store/

PRIVACY.md

@@ -0,0 +1,28 @@
+# Privacy Policy
+
+The canonical Smirk privacy policy lives at **https://smirk.cash/privacy** and
+describes the data practices of the instance operated by Such Software LLC
+(api.smirk.cash).
+
+## For operators who self-host
+
+This backend is open source and self-hostable. **If you run your own instance, you
+are an independent data controller for it** and the Such Software policy does not
+speak for you. What your instance receives from wallets that connect to it:
+
+- **Monero/Wownero view keys** (to scan for users' incoming funds; a view key
+  cannot spend) and their scan/registration state.
+- **Public addresses** for BTC/LTC balance lookups and **signed transactions** to
+  broadcast. Recipient address and amount are not sent on broadcast.
+- A one-way **seed fingerprint** (SHA-256) as a non-reversible wallet identifier.
+- If enabled: the **username to npub** mapping published in your NIP-05 directory,
+  and, for the relay, encrypted message envelopes (ciphertext only).
+- IP addresses only as a **salted one-way hash**, for rate-limiting.
+
+Private keys and seed phrases are never transmitted to the backend.
+
+If you offer your instance to others, publish your own privacy policy describing
+how you handle this data, your retention, and your jurisdiction. The knobs that
+affect retention and data exposure (login-event and audit retention, erasure,
+relay retention, landing-page exposure) are documented in
+[docs/operations/CONSOLE.md](docs/operations/CONSOLE.md) and the root `.env.example`.

tools/secret-scan.sh

@@ -17,8 +17,12 @@ else
   mapfile -t FILES < <(find . -type f -not -path './.git/*' -not -path './target/*' -printf '%P\n')
 fi
 
-# Secret shapes (not names): PEM/OpenSSH/PGP private-key blocks and seed phrases.
-PATTERNS='(-----BEGIN ([A-Z ]+ )?PRIVATE KEY-----|-----BEGIN PGP PRIVATE KEY|BEGIN OPENSSH PRIVATE KEY|\b(mnemonic|seed[_ ]?phrase)\b\s*[:=])'
+# Secret shapes (not names), covering the classes this backend actually handles:
+#   - PEM/OpenSSH/PGP private-key blocks and seed-phrase markers
+#   - nsec1... Nostr SECRET keys (bech32)
+#   - a *_PEPPER / *_SALT (or admin key/secret) assigned a 32+ hex-char value, i.e.
+#     an `openssl rand -hex 32` peppered secret pasted in cleartext
+PATTERNS='(-----BEGIN ([A-Z ]+ )?PRIVATE KEY-----|-----BEGIN PGP PRIVATE KEY|BEGIN OPENSSH PRIVATE KEY|\b(mnemonic|seed[_ ]?phrase)\b\s*[:=]|nsec1[0-9a-z]{20,}|\b[A-Z_]*(PEPPER|SALT|INTEGRITY_SECRET)[A-Z_]*\s*=\s*[0-9a-fA-F]{32,})'
 
 fail=0
 for f in "${FILES[@]}"; do