diff --git a/CHECKPOINT-encryption.md b/CHECKPOINT-encryption.md
index 8c20051..1b3748a 100644
--- a/CHECKPOINT-encryption.md
+++ b/CHECKPOINT-encryption.md
@@ -1,4 +1,4 @@
-# Checkpoint — Owner-only-from-first-byte file writes (2026-08-21)
+# Checkpoint — Key material zeroization (2026-08-21)
 
 A stopping point you can return to if this session is closed. Everything below was
 verified green at the moment this file was written.
@@ -6,13 +6,12 @@ verified green at the moment this file was written.
 ## Where things are
 
 - Project: `/home/avi/Projects/0_Nostr`
-- Git repo: `master` @ `4461307` ("Create vault files owner-only from the first byte").
-  Before it: `4bd7660` (legacy vault perms), `4d4dfde` (CSP + navigation guards),
-  `6e627a3` (upload pick tokens), `4bde395` (IPC allowlist), on top of contact-aware
-  feed (`a1445d1`) etc.
+- Git repo: `master` @ `130d7e2` ("Zeroize transient secret key material in memory").
+  Before it: `4461307` (owner-only writes), `4bd7660` (legacy vault perms), `4d4dfde`
+  (CSP + navigation guards), `6e627a3` (upload pick tokens), `4bde395` (IPC allowlist).
 - Working tree is **clean** apart from this checkpoint update, which is committed right after.
 
-## What was completed: security hardening items #1–#5
+## What was completed: security hardening items #1–#6
 
 Fixes from the 2026-08-21 security audit.
 
@@ -80,8 +79,24 @@ page could read+publish arbitrary local files to nostr.build. Now:
   with a manual open-at-0600 + `io::copy`, making backups owner-only from their first byte.
 - New test: backup of a 0664 source comes out 0600 with identical content.
 
+**#6 Key material zeroization (`130d7e2`, adds `zeroize = "1"`):**
+Decrypted secrets and derived keys no longer linger in unscrubbed heap memory:
+- `crypto.rs`: `decrypt_secret` returns `Zeroizing<String>` (self-shredding on drop); the
+  UTF-8 error path wipes the raw bytes too; a failed Argon2 derivation wipes its key buffer.
+- `profiles.rs`: `resolve_secret_key` / `resolve_active_secret_key` now return
+  `Zeroizing<String>`, so every transient plaintext key flowing to publish/upload/signer is
+  wiped when its scope ends. Newly generated keys in `create_profile` are wrapped the same
+  way. `reveal_secret_key` still hands a display copy to the UI by design.
+- `app.rs`: `lock()` and a new `Drop for App` zeroize the session vault key; wrong-password
+  derivations wipe their throwaway keys; password change wipes the previous vault key and
+  the old unlock key; `remove_password` moves decrypted values into storage via
+  `std::mem::take` without extra copies (plaintext-at-rest is that feature's purpose).
+- Callers in `publish.rs`, `uploads.rs`, `signer.rs` needed no changes (deref coercion).
+
 ## Commits
 
+- `130d7e2` "Zeroize transient secret key material in memory" — Cargo.toml, crypto.rs,
+  profiles.rs, app.rs (+77/−23).
 - `4461307` "Create vault files owner-only from the first byte" — src/vault.rs (+48/−2).
 - `4bd7660` "Tighten permissions on leftover legacy vault files" — src/vault.rs (+79/−3).
 - `4d4dfde` "Enforce header-based CSP and block window open/navigation" — main.ts + index.html.
@@ -122,12 +137,13 @@ Manual protocol checks worth doing once:
 
 ## Outstanding / next steps (if you continue)
 
-Remaining audit items in priority order:
+Remaining smaller hardening items from the audit:
 
-1. **Zeroize** — wipe decrypted key material via the `zeroize` crate (`VaultKey`,
-   decrypted hex strings in `crypto.rs`/`profiles.rs`).
-2. Smaller: link-preview SSRF guard (block loopback/private IPs), signer pending-cap,
-   NIP-46 secret echo check, backend request timeout.
+1. Link-preview SSRF guard — block loopback/private IPs in `fetchLinkPreview` (`main.ts`).
+2. Signer pending-cap — bound the approval queue (e.g. max 10) against relay spam.
+3. NIP-46 secret echo check — verify the client echoes the handshake `secret`.
+4. Backend request timeout — `backendRequest` in `main.ts` has no timeout; hung backend
+   leaks pending promises.
 
-All five medium findings from the audit are closed (#1 IPC allowlist, #2 upload tokens,
-#3 CSP + navigation, #4 legacy vault perms, #5 write-race windows).
+All six primary findings are closed (#1 IPC allowlist, #2 upload tokens, #3 CSP +
+navigation, #4 legacy vault perms, #5 write-race windows, #6 zeroization).