# Plan 4: Security Blocker Fixes

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Clear all 4 audit blockers (B1-B4) + important items (I1-I6) + HOTP bug before v0.3.0

**Architecture:** Fix security-theater device keys by removal (not implementation), add missing validations/normalizations, and harden path handling. HOTP is disabled with a clear error since counter persistence requires vault save machinery that doesn't exist.

**Tech Stack:** Rust (relicario-core, relicario-cli, relicario-wasm), TypeScript (extension)

---

## File Structure

### Core changes
- `crates/relicario-core/src/backup.rs` — add NFC normalization (B2)
- `crates/relicario-core/src/ids.rs` — expand AttachmentId to 128 bits (I2)
- `crates/relicario-core/src/item_types/totp.rs` — reject HOTP with error (I6)
- `crates/relicario-core/src/error.rs` — add HotpNotSupported variant

### CLI changes
- `crates/relicario-cli/src/main.rs`:
  - Remove Device subcommand/enum/handler (B1)
  - Remove devices.json from init (B1)
  - Gate test env vars with #[cfg(test)] (B3)
  - Validate IDs on restore (B4)
  - Sanitize titles in commit messages (I1)
  - Enforce per-vault attachment cap (I3)
- `crates/relicario-cli/src/helpers.rs` — add `sanitize_for_commit()` (I1)
- `crates/relicario-cli/tests/basic_flows.rs` — remove devices.json assertion (B1)

### WASM changes
- `crates/relicario-wasm/src/lib.rs` — remove `generate_device_keypair` (B1/I5)

### Extension changes (B1)
- Remove `extension/src/popup/components/devices.ts`
- Remove `extension/src/popup/components/__tests__/devices.test.ts`
- Remove `extension/src/service-worker/devices.ts`
- Remove `extension/src/service-worker/__tests__/devices.test.ts`
- Update `extension/src/shared/messages.ts` — remove device message types
- Update `extension/src/shared/types.ts` — remove Device type
- Update `extension/src/popup/popup.ts` — remove devices route
- Update `extension/src/popup/components/settings.ts` — remove devices link
- Update `extension/src/service-worker/router/popup-only.ts` — remove device handlers
- Update `extension/src/wasm.d.ts` — remove generate_device_keypair

### Documentation (I4)
- `docs/SECURITY.md` — document manifest integrity model

---

## Task 1: Remove device key system from CLI (B1)

**Files:**
- Modify: `crates/relicario-cli/src/main.rs:165-168, 315-320, 388, 500, 518, 2151-2221`
- Modify: `crates/relicario-cli/tests/basic_flows.rs:11`

- [ ] **Step 1: Write test that init does NOT create devices.json**

```rust
// In crates/relicario-cli/tests/basic_flows.rs, modify init_creates_expected_layout:
#[test]
fn init_creates_expected_layout() {
    let v = TestVault::init();
    assert!(v.path().join(".relicario/salt").exists());
    assert!(v.path().join(".relicario/params.json").exists());
    // devices.json removed — device key system was security theater
    assert!(!v.path().join(".relicario/devices.json").exists());
    assert!(v.path().join("manifest.enc").exists());
    assert!(v.path().join("settings.enc").exists());
    assert!(v.path().join("reference.jpg").exists());
    assert!(v.path().join(".gitignore").exists());
    assert!(v.path().join(".git").is_dir());
}
```

- [ ] **Step 2: Run test to verify it fails**

Run: `cargo test -p relicario-cli --test basic_flows init_creates_expected_layout`
Expected: FAIL — devices.json still exists

- [ ] **Step 3: Remove DeviceAction enum**

In `main.rs`, delete lines 315-320:

```rust
// DELETE THIS BLOCK:
#[derive(Subcommand)]
enum DeviceAction {
    Add { #[arg(long)] name: String },
    List,
    Revoke { name: String },
}
```

- [ ] **Step 4: Remove Device variant from Commands enum**

In `main.rs`, delete lines 164-168:

```rust
// DELETE THIS BLOCK:
    /// Device management.
    Device {
        #[command(subcommand)]
        action: DeviceAction,
    },
```

- [ ] **Step 5: Remove Device match arm**

In `main.rs`, delete line 388:

```rust
// DELETE THIS LINE:
        Commands::Device { action } => cmd_device(action),
```

- [ ] **Step 6: Remove devices.json creation in cmd_init**

In `main.rs`, delete line 500:

```rust
// DELETE THIS LINE:
    fs::write(relicario_dir.join("devices.json"), b"[]")?;
```

- [ ] **Step 7: Remove devices.json from git add in cmd_init**

In `main.rs` line 517-519, change:

```rust
// FROM:
    let _ = crate::helpers::git_command(&root, &[
        "add", ".gitignore", ".relicario/params.json", ".relicario/devices.json",
        ".relicario/salt", "manifest.enc", "settings.enc",
    ]).status()?;

// TO:
    let _ = crate::helpers::git_command(&root, &[
        "add", ".gitignore", ".relicario/params.json",
        ".relicario/salt", "manifest.enc", "settings.enc",
    ]).status()?;
```

- [ ] **Step 8: Remove cmd_device function**

Delete the entire `cmd_device` function (lines 2151-2221).

- [ ] **Step 9: Run test to verify it passes**

Run: `cargo test -p relicario-cli --test basic_flows init_creates_expected_layout`
Expected: PASS

- [ ] **Step 10: Run full CLI test suite**

Run: `cargo test -p relicario-cli`
Expected: All tests pass (some may need adjustment if they reference devices)

- [ ] **Step 11: Commit**

```bash
git add crates/relicario-cli/
git commit -m "$(cat <<'EOF'
fix(cli): remove device key system (audit B1)

The device add/list/revoke commands generated and stored ed25519 keys
but no code ever signed commits or verified signatures. This gave users
a false sense of security around device revocation.

Removed: Device subcommand, DeviceAction enum, cmd_device handler,
devices.json creation. Access control remains SSH-key-level only.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 2: Remove device key system from WASM (B1/I5)

**Files:**
- Modify: `crates/relicario-wasm/src/lib.rs:212-227`

- [ ] **Step 1: Remove generate_device_keypair function**

Delete lines 212-227 in `lib.rs`:

```rust
// DELETE THIS BLOCK:
/// Generate an ed25519 keypair for device registration.
/// Returns JSON: { "public_key_hex": "...", "private_key_base64": "..." }
#[wasm_bindgen]
pub fn generate_device_keypair() -> Result<JsValue, JsError> {
    let mut rng = rand::thread_rng();
    let signing_key = SigningKey::generate(&mut rng);
    let verifying_key = signing_key.verifying_key();

    let public_hex = hex::encode(verifying_key.as_bytes());
    let private_b64 = base64::engine::general_purpose::STANDARD.encode(signing_key.as_bytes());

    js_value_for(&serde_json::json!({
        "public_key_hex": public_hex,
        "private_key_base64": private_b64,
    }))
}
```

- [ ] **Step 2: Remove ed25519_dalek import if no longer needed**

Check if `SigningKey` is used elsewhere. If not, remove the import.

- [ ] **Step 3: Build WASM to verify compilation**

Run: `cargo build -p relicario-wasm --target wasm32-unknown-unknown`
Expected: Build succeeds

- [ ] **Step 4: Commit**

```bash
git add crates/relicario-wasm/
git commit -m "$(cat <<'EOF'
fix(wasm): remove generate_device_keypair (audit B1/I5)

Private key was being returned to JS heap with no Zeroizing protection.
The entire device key system is removed as security theater.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 3: Remove device UI from extension (B1)

**Files:**
- Delete: `extension/src/popup/components/devices.ts`
- Delete: `extension/src/popup/components/__tests__/devices.test.ts`
- Delete: `extension/src/service-worker/devices.ts`
- Delete: `extension/src/service-worker/__tests__/devices.test.ts`
- Modify: `extension/src/shared/messages.ts`
- Modify: `extension/src/shared/types.ts`
- Modify: `extension/src/popup/popup.ts`
- Modify: `extension/src/popup/components/settings.ts`
- Modify: `extension/src/service-worker/router/popup-only.ts`
- Modify: `extension/src/wasm.d.ts`

- [ ] **Step 1: Delete device component files**

```bash
rm extension/src/popup/components/devices.ts
rm extension/src/popup/components/__tests__/devices.test.ts
rm extension/src/service-worker/devices.ts
rm extension/src/service-worker/__tests__/devices.test.ts
```

- [ ] **Step 2: Remove Device type from types.ts**

Find and remove the `Device` interface in `extension/src/shared/types.ts`.

- [ ] **Step 3: Remove device message types from messages.ts**

Find and remove `list_devices`, `register_device`, `revoke_device` message types.

- [ ] **Step 4: Remove devices route from popup.ts**

Remove the devices case from the route switch and the import.

- [ ] **Step 5: Remove devices link from settings.ts**

Find and remove the "Devices" button/link in the settings view.

- [ ] **Step 6: Remove device handlers from popup-only.ts**

Remove the `list_devices`, `register_device`, `revoke_device` handlers.

- [ ] **Step 7: Remove generate_device_keypair from wasm.d.ts**

Delete line 64 in `extension/src/wasm.d.ts`:

```typescript
// DELETE THIS LINE:
  export function generate_device_keypair(): { public_key_hex: string; private_key_base64: string };
```

- [ ] **Step 8: Run TypeScript check**

Run: `cd extension && npm run typecheck`
Expected: No errors

- [ ] **Step 9: Run extension tests**

Run: `cd extension && npm test`
Expected: All tests pass (device tests are deleted)

- [ ] **Step 10: Commit**

```bash
git add extension/
git commit -m "$(cat <<'EOF'
fix(extension): remove device UI (audit B1)

Device registration/revocation provided no real security since the
underlying signing infrastructure was never implemented. Removed all
device-related components, message handlers, and type definitions.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 4: Fix backup KDF NFC normalization (B2)

**Files:**
- Modify: `crates/relicario-core/src/backup.rs:303-312`
- Create test in: `crates/relicario-core/tests/backup.rs` (or add to existing)

- [ ] **Step 1: Write failing test for NFC normalization**

```rust
// In crates/relicario-core/tests/backup.rs or a new test file:
#[test]
fn backup_kdf_normalizes_nfc() {
    use relicario_core::backup::{pack, unpack};
    
    // "café" in NFD (decomposed: e + combining acute) vs NFC (composed: é)
    let nfd_passphrase = "caf\u{0065}\u{0301}"; // e + combining accent
    let nfc_passphrase = "caf\u{00E9}";          // precomposed é
    
    // Create a minimal backup with NFD passphrase
    let input = BackupInput {
        salt: &[0u8; 32],
        params_json: b"{}",
        devices_json: b"[]",
        manifest_enc: &[1, 2, 3],
        settings_enc: &[4, 5, 6],
        items: vec![],
        attachments: vec![],
    };
    
    let packed = pack(input, nfd_passphrase, false, false).unwrap();
    
    // Unpack with NFC passphrase — should work because both normalize to same
    let unpacked = unpack(&packed, nfc_passphrase).unwrap();
    assert_eq!(unpacked.manifest_enc, vec![1, 2, 3]);
}
```

- [ ] **Step 2: Run test to verify it fails**

Run: `cargo test -p relicario-core backup_kdf_normalizes_nfc`
Expected: FAIL — NFD and NFC produce different keys

- [ ] **Step 3: Add NFC normalization to derive_backup_key**

In `backup.rs`, modify `derive_backup_key`:

```rust
fn derive_backup_key(passphrase: &[u8], salt: &[u8]) -> Result<Zeroizing<[u8; 32]>> {
    use unicode_normalization::UnicodeNormalization;
    
    // NFC normalize passphrase (same as derive_master_key in crypto.rs)
    let nfc_passphrase: Vec<u8> = match std::str::from_utf8(passphrase) {
        Ok(s) => s.nfc().collect::<String>().into_bytes(),
        Err(_) => passphrase.to_vec(),
    };
    
    let params = Params::new(ARGON2_M_KIB, ARGON2_T, ARGON2_P, Some(32))
        .map_err(|e| RelicarioError::Kdf(format!("argon2 params: {e}")))?;
    let argon = Argon2::new(Algorithm::Argon2id, Version::V0x13, params);
    let mut key = Zeroizing::new([0u8; 32]);
    argon
        .hash_password_into(&nfc_passphrase, salt, key.as_mut_slice())
        .map_err(|e| RelicarioError::Kdf(format!("argon2 hash: {e}")))?;
    Ok(key)
}
```

- [ ] **Step 4: Run test to verify it passes**

Run: `cargo test -p relicario-core backup_kdf_normalizes_nfc`
Expected: PASS

- [ ] **Step 5: Commit**

```bash
git add crates/relicario-core/
git commit -m "$(cat <<'EOF'
fix(core): NFC normalize backup passphrase (audit B2)

Backup KDF was passing raw passphrase bytes to Argon2id without NFC
normalization, causing cross-platform restore failures for non-ASCII
passphrases (macOS NFD vs Linux NFC).

Now matches derive_master_key behavior from crypto.rs.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 5: Gate test env vars with #[cfg(test)] (B3)

**Files:**
- Modify: `crates/relicario-cli/src/main.rs:417-450, 1425-1430, 1594`

- [ ] **Step 1: Identify all test env var locations**

Locations found:
- Lines 417-423: `RELICARIO_TEST_ITEM_SECRET`
- Lines 443-450: `RELICARIO_TEST_PASSPHRASE`
- Lines 1425-1430: `RELICARIO_TEST_BACKUP_PASSPHRASE`
- Line 1594: `RELICARIO_TEST_BACKUP_PASSPHRASE`

- [ ] **Step 2: Wrap prompt_item_secret test bypass**

```rust
// Lines 417-423, change:
fn prompt_item_secret(prompt: &str) -> Result<Zeroizing<String>> {
    #[cfg(test)]
    if let Ok(s) = std::env::var("RELICARIO_TEST_ITEM_SECRET") {
        return Ok(Zeroizing::new(s));
    }
    
    let pass = rpassword::prompt_password(prompt)
        .context("failed to read secret")?;
    Ok(Zeroizing::new(pass))
}
```

- [ ] **Step 3: Wrap prompt_passphrase test bypass**

```rust
// Lines 443-450, change:
fn prompt_passphrase(prompt: &str, confirm: bool) -> Result<Zeroizing<String>> {
    #[cfg(test)]
    let passphrase = if let Ok(p) = std::env::var("RELICARIO_TEST_PASSPHRASE") {
        Zeroizing::new(p)
    } else {
        Zeroizing::new(rpassword::prompt_password(prompt).context("failed to read passphrase")?)
    };
    
    #[cfg(not(test))]
    let passphrase = Zeroizing::new(rpassword::prompt_password(prompt).context("failed to read passphrase")?);
    
    #[cfg(test)]
    let confirm_skip = std::env::var_os("RELICARIO_TEST_PASSPHRASE").is_some();
    #[cfg(not(test))]
    let confirm_skip = false;
    
    if confirm && !confirm_skip {
        // ... existing confirm logic
    }
    Ok(passphrase)
}
```

- [ ] **Step 4: Wrap backup passphrase test bypass (export)**

Apply same pattern to lines 1425-1430.

- [ ] **Step 5: Wrap backup passphrase test bypass (restore)**

Apply same pattern to line 1594.

- [ ] **Step 6: Build release binary and verify env vars are not present**

Run: `cargo build -p relicario-cli --release && strings target/release/relicario | grep RELICARIO_TEST`
Expected: No output (strings not present in release binary)

- [ ] **Step 7: Run tests to verify they still work**

Run: `cargo test -p relicario-cli`
Expected: All tests pass

- [ ] **Step 8: Commit**

```bash
git add crates/relicario-cli/
git commit -m "$(cat <<'EOF'
fix(cli): gate test env vars with #[cfg(test)] (audit B3)

RELICARIO_TEST_PASSPHRASE and friends were checked in production code,
exposing the passphrase via /proc/<pid>/environ and shell history.

Now only compiled into test binaries.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 6: Validate IDs on backup restore (B4)

**Files:**
- Modify: `crates/relicario-cli/src/main.rs:1619-1626`
- Modify: `crates/relicario-core/src/ids.rs` (add validation function)

- [ ] **Step 1: Write failing test for path traversal**

```rust
// In crates/relicario-cli/tests/attachments.rs or backup tests:
#[test]
fn restore_rejects_traversal_ids() {
    // Create a backup with malicious item ID
    // Attempt restore
    // Expect error, not file write outside target
}
```

- [ ] **Step 2: Add is_valid_id function to ids.rs**

```rust
impl ItemId {
    /// Returns true if this ID is safe for use in filesystem paths.
    /// Valid IDs are 16 hex characters (8 bytes).
    pub fn is_valid(&self) -> bool {
        self.0.len() == 16 && self.0.chars().all(|c| c.is_ascii_hexdigit())
    }
}

impl AttachmentId {
    /// Returns true if this ID is safe for use in filesystem paths.
    /// Valid IDs are 32 hex characters (16 bytes) after I2 fix.
    pub fn is_valid(&self) -> bool {
        self.0.len() == 32 && self.0.chars().all(|c| c.is_ascii_hexdigit())
    }
}
```

- [ ] **Step 3: Validate IDs during restore**

In `main.rs` around line 1619, add validation:

```rust
for item in &unpacked.items {
    if !item.id.is_valid() {
        anyhow::bail!("invalid item ID in backup: {}", item.id.as_str());
    }
    fs::write(target.join("items").join(format!("{}.enc", item.id)), &item.ciphertext)?;
}
for a in &unpacked.attachments {
    if !a.item_id.is_valid() || !a.attachment_id.is_valid() {
        anyhow::bail!("invalid attachment ID in backup");
    }
    let dir = target.join("attachments").join(&a.item_id);
    fs::create_dir_all(&dir)?;
    fs::write(dir.join(format!("{}.enc", a.attachment_id)), &a.ciphertext)?;
}
```

- [ ] **Step 4: Run test to verify it passes**

Run: `cargo test -p relicario-cli restore_rejects_traversal`
Expected: PASS

- [ ] **Step 5: Commit**

```bash
git add crates/relicario-core/src/ids.rs crates/relicario-cli/
git commit -m "$(cat <<'EOF'
fix(cli): validate IDs on backup restore (audit B4)

Crafted .relbak files with IDs like "../../.bashrc" could escape the
target directory. Now validates that item/attachment IDs are hex-only
before any fs::write.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 7: Sanitize item titles in commit messages (I1)

**Files:**
- Modify: `crates/relicario-cli/src/helpers.rs`
- Modify: `crates/relicario-cli/src/main.rs:565, 1110, 1327`

- [ ] **Step 1: Add sanitize_for_commit to helpers.rs**

```rust
/// Sanitize a string for use in git commit messages.
/// Removes control characters and truncates to 50 chars.
pub fn sanitize_for_commit(s: &str) -> String {
    s.chars()
        .filter(|c| !c.is_control())
        .take(50)
        .collect()
}
```

- [ ] **Step 2: Use sanitize_for_commit in add commit**

```rust
// Line 565, change:
commit_paths(&vault, &format!("add: {} ({})", 
    crate::helpers::sanitize_for_commit(&item.title), 
    item.id.as_str()), &path_refs)?;
```

- [ ] **Step 3: Use sanitize_for_commit in edit commit**

```rust
// Line 1110, change:
commit_paths(&vault, &format!("edit: {} ({})", 
    crate::helpers::sanitize_for_commit(&item.title), 
    item.id.as_str()),
```

- [ ] **Step 4: Use sanitize_for_commit in trash commit**

```rust
// Line 1327, change:
commit_paths(&vault, &format!("trash: {} ({})", 
    crate::helpers::sanitize_for_commit(&item.title), 
    item.id.as_str()),
```

- [ ] **Step 5: Write test for sanitization**

```rust
#[test]
fn sanitize_for_commit_strips_newlines() {
    assert_eq!(sanitize_for_commit("line1\nline2"), "line1line2");
    assert_eq!(sanitize_for_commit("a\tb"), "ab");
    assert_eq!(sanitize_for_commit("normal"), "normal");
}
```

- [ ] **Step 6: Run tests**

Run: `cargo test -p relicario-cli`
Expected: PASS

- [ ] **Step 7: Commit**

```bash
git add crates/relicario-cli/
git commit -m "$(cat <<'EOF'
fix(cli): sanitize item titles in commit messages (audit I1)

Control characters (newlines, tabs) in item titles corrupted git log
output. Now strips control chars and truncates to 50 chars.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 8: Expand AttachmentId to 128 bits (I2)

**Files:**
- Modify: `crates/relicario-core/src/ids.rs:54`

- [ ] **Step 1: Write test for 128-bit AttachmentId**

```rust
#[test]
fn attachment_id_is_128_bits() {
    let id = AttachmentId::from_plaintext(b"test content");
    assert_eq!(id.as_str().len(), 32); // 16 bytes = 32 hex chars
}
```

- [ ] **Step 2: Run test to verify it fails**

Run: `cargo test -p relicario-core attachment_id_is_128_bits`
Expected: FAIL — currently 16 hex chars (64 bits)

- [ ] **Step 3: Change digest slice from 8 to 16 bytes**

```rust
// Line 54, change:
// FROM:
Self(hex::encode(&digest[..8]))
// TO:
Self(hex::encode(&digest[..16]))
```

- [ ] **Step 4: Run test to verify it passes**

Run: `cargo test -p relicario-core attachment_id_is_128_bits`
Expected: PASS

- [ ] **Step 5: Update is_valid() in Task 6 if already implemented**

Ensure `AttachmentId::is_valid()` checks for 32 chars, not 16.

- [ ] **Step 6: Run full test suite**

Run: `cargo test`
Expected: All tests pass

- [ ] **Step 7: Commit**

```bash
git add crates/relicario-core/
git commit -m "$(cat <<'EOF'
fix(core): expand AttachmentId to 128 bits (audit I2)

64-bit truncation allowed birthday collisions at ~2^32 work. Now uses
16 bytes (128 bits) of SHA-256, requiring ~2^64 work for collision.

No migration needed — only affects new attachments.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 9: Enforce per-vault attachment cap (I3)

**Files:**
- Modify: `crates/relicario-cli/src/main.rs` — cmd_attach function

- [ ] **Step 1: Find cmd_attach and calculate vault total**

In `cmd_attach`, before calling `encrypt_attachment`, sum existing attachment sizes from manifest.

- [ ] **Step 2: Implement vault-level cap check**

```rust
// In cmd_attach, after loading manifest and settings:
let current_total: u64 = manifest.items.values()
    .flat_map(|entry| &entry.attachments)
    .map(|a| a.size)
    .sum();

let new_size = bytes.len() as u64;
let hard_cap = settings.attachment_caps.per_vault_hard_cap_bytes;

if current_total + new_size > hard_cap {
    anyhow::bail!(
        "attachment would exceed vault cap ({} + {} > {} bytes)",
        current_total, new_size, hard_cap
    );
}

let soft_cap = settings.attachment_caps.per_vault_soft_cap_bytes;
if current_total + new_size > soft_cap {
    eprintln!("warning: vault attachment total exceeds soft cap ({} bytes)", soft_cap);
}
```

- [ ] **Step 3: Write test for cap enforcement**

```rust
#[test]
fn attach_enforces_vault_cap() {
    // Create vault with low hard cap in settings
    // Add attachments until cap is hit
    // Verify next attachment fails
}
```

- [ ] **Step 4: Run tests**

Run: `cargo test -p relicario-cli`
Expected: PASS

- [ ] **Step 5: Commit**

```bash
git add crates/relicario-cli/
git commit -m "$(cat <<'EOF'
fix(cli): enforce per-vault attachment bytes cap (audit I3)

per_vault_soft_cap_bytes and per_vault_hard_cap_bytes were defined in
VaultSettings but never checked. Now enforced in cmd_attach with
warning at soft cap, error at hard cap.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 10: Disable HOTP with clear error (I6)

**Files:**
- Modify: `crates/relicario-core/src/error.rs`
- Modify: `crates/relicario-core/src/item_types/totp.rs:71-76`

- [ ] **Step 1: Add HotpNotSupported error variant**

```rust
// In error.rs:
#[derive(Debug, Error)]
pub enum RelicarioError {
    // ... existing variants ...
    
    #[error("HOTP is not supported: counter persistence requires vault save")]
    HotpNotSupported,
}
```

- [ ] **Step 2: Reject HOTP in compute_totp_code**

```rust
// In totp.rs, compute_totp_code:
pub fn compute_totp_code(config: &TotpConfig, now_unix_seconds: u64) -> Result<String> {
    let counter = match config.kind {
        TotpKind::Totp => now_unix_seconds / config.period_seconds as u64,
        TotpKind::Hotp { .. } => return Err(RelicarioError::HotpNotSupported),
        TotpKind::Steam => now_unix_seconds / config.period_seconds as u64,
    };
    // ... rest unchanged
}
```

- [ ] **Step 3: Update HOTP test to expect error**

```rust
#[test]
fn hotp_returns_not_supported_error() {
    let cfg = TotpConfig { kind: TotpKind::Hotp { counter: 42 }, ..TotpConfig::default() };
    let result = compute_totp_code(&cfg, 0);
    assert!(matches!(result, Err(RelicarioError::HotpNotSupported)));
}
```

- [ ] **Step 4: Run tests**

Run: `cargo test -p relicario-core`
Expected: PASS (after updating any tests that expected HOTP to work)

- [ ] **Step 5: Commit**

```bash
git add crates/relicario-core/
git commit -m "$(cat <<'EOF'
fix(core): disable HOTP with clear error (audit I6)

HOTP requires incrementing and persisting the counter after each use.
Without vault-save machinery in compute_totp_code, HOTP would desync
immediately. Now returns HotpNotSupported error.

TOTP and Steam codes continue to work.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 11: Document manifest integrity model (I4)

**Files:**
- Create: `docs/SECURITY.md`

- [ ] **Step 1: Write SECURITY.md**

```markdown
# Relicario Security Model

## Manifest Integrity

The manifest (`manifest.enc`) is encrypted with AEAD (XChaCha20-Poly1305), which provides:

- **Confidentiality**: Contents are unreadable without the master key
- **Integrity**: Any modification is detected and rejected on decrypt
- **Authenticity**: Only holders of the master key can create valid ciphertexts

### What AEAD Does NOT Protect

- **Item deletion**: An attacker with write access to the vault can delete
  `.enc` files or git-revert commits. The manifest will decrypt successfully
  but won't contain the deleted items.

- **Rollback attacks**: An attacker can replace `manifest.enc` with an older
  valid version. AEAD accepts any ciphertext created with the correct key.

### Mitigation

Item deletion and rollback are detectable via **git history**. The git log
provides an append-only audit trail:

```bash
git log --oneline items/
```

For environments where git history could be rewritten (e.g., force-push),
consider:

1. A pre-receive hook that rejects non-fast-forward pushes
2. Signed commits (not currently implemented)
3. Regular backups with `relicario backup export`

## Access Control

Relicario does not implement device-level access control. All access control
is at the transport layer:

- **CLI**: SSH key authentication to the git remote
- **Extension**: Git credentials stored in browser profile

Device registration/revocation was removed in v0.3.0 as it provided no
actual security benefit without commit signing infrastructure.
```

- [ ] **Step 2: Commit**

```bash
git add docs/SECURITY.md
git commit -m "$(cat <<'EOF'
docs: document manifest integrity model (audit I4)

Clarifies what AEAD protects (tampering) vs. what it doesn't (deletion,
rollback). Documents that git history is the audit trail.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 12: Update backup to not include devices.json (B1 cleanup)

**Files:**
- Modify: `crates/relicario-core/src/backup.rs:61, 138`
- Modify: `crates/relicario-cli/src/main.rs:1447-1448, 1615`

- [ ] **Step 1: Remove devices_json from BackupInput struct**

In `backup.rs`, remove the `devices_json` field from `BackupInput` and `UnpackedBackup`.

- [ ] **Step 2: Update pack/unpack to not include devices**

Remove all references to `devices_json` in the pack/unpack logic.

- [ ] **Step 3: Update CLI export to not read devices.json**

Remove lines 1447-1448 that read devices.json.

- [ ] **Step 4: Update CLI restore to not write devices.json**

Remove line 1615 that writes devices.json.

- [ ] **Step 5: Run backup tests**

Run: `cargo test -p relicario-cli --test attachments`
Run: `cargo test -p relicario-core`
Expected: PASS

- [ ] **Step 6: Commit**

```bash
git add crates/relicario-core/ crates/relicario-cli/
git commit -m "$(cat <<'EOF'
fix(backup): remove devices.json from backup format (B1 cleanup)

Part of device key system removal. Backup files no longer include
devices.json since the device registration system is removed.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
EOF
)"
```

---

## Task 13: Final verification

- [ ] **Step 1: Run full test suite**

Run: `cargo test`
Expected: All tests pass

- [ ] **Step 2: Build all targets**

```bash
cargo build
cargo build -p relicario-wasm --target wasm32-unknown-unknown
cd extension && npm run build
```
Expected: All builds succeed

- [ ] **Step 3: Manual smoke test**

```bash
# Create new vault
relicario init test.jpg --output ref.jpg

# Verify no devices.json
ls .relicario/
# Should show: params.json, salt (no devices.json)

# Add item with special chars in title
relicario add login --title $'Test\nNewline' --username test

# Check git log for sanitized commit message
git log -1 --oneline
# Should show: add: TestNewline (...)
```

- [ ] **Step 4: Commit verification summary**

```bash
git log --oneline -15
```

Verify all 12+ commits are present with appropriate messages.

---

## Completion Checklist

- [ ] B1: Device key system removed (CLI, WASM, extension, backup)
- [ ] B2: Backup KDF NFC normalization
- [ ] B3: Test env vars gated with #[cfg(test)]
- [ ] B4: Path traversal validation on restore
- [ ] I1: Item titles sanitized in commits
- [ ] I2: AttachmentId expanded to 128 bits
- [ ] I3: Per-vault attachment cap enforced
- [ ] I4: SECURITY.md documents manifest integrity
- [ ] I5: (Covered by B1 — generate_device_keypair removed)
- [ ] I6: HOTP returns HotpNotSupported error
- [ ] All tests pass
- [ ] All builds succeed