test: known-answer coverage for HD derivation and the vault (closes #159)

wallet.js and vault.js — the two modules that hold user funds — had no
derivation or encryption tests. Add them, pinned to published vectors
rather than to whatever the implementation returns today.

wallet.js: hdWalletFromMnemonic, hdWalletFromXprv, deriveAddressFromXpub
and getSignerForAddress are pinned to the standard development recovery
phrase's first three accounts at m/44'/60'/0'/0/n and to the BIP-39
all-zero-entropy phrase's first address; addressFromPrivateKey is pinned
to the published key/address pairs, so the HD path and the bare-key path
must meet at the same address from two directions. isValidMnemonic and
isValidXprv cover bad checksum, wrong word count, wrong key type and
empty/garbage input. The absolute-vs-relative path asymmetry between
hdWalletFromMnemonic and hdWalletFromXprv is proven harmless: for the
same master key both reach the same xpub and the same addresses.

vault.js: round trip (including non-ASCII and an empty password), wrong
password rejected as a rejected promise with no partial plaintext,
tampered ciphertext / auth tag / nonce / salt rejected, truncated and
spliced blobs rejected, missing fields rejected, fresh salt and nonce per
encryption, the documented { salt, nonce, ciphertext } shape, and no
trace of the plaintext or password anywhere in the serialized blob. The
Argon2id cost parameters are pinned three ways — the INTERACTIVE
constants still mean 2 passes over 64 MiB, a key independently derived at
that cost opens the vault, and both encrypt and decrypt are observed
calling crypto_pwhash with those constants — because the KDF cost is the
vault's only defence against offline attack on a stolen blob and nothing
else in the suite would notice it being lowered. The tamper cases share
one encrypted fixture to stay inside script/test's 30-second budget.

One test is skipped: isValidXprv accepts an extended private key with a
one-character typo, because ethers skips base58 checksum verification for
the usual 82-byte payload. That defect is tracked separately and is not
fixed here; the skipped test asserts the correct behaviour and cites the
issue.

.dockerignore

@@ -1,3 +1,6 @@
+# .git is deliberately NOT excluded: build.js shells out to `git rev-parse` for
+# build-info stamping and the Dockerfile runs `make build`, so excluding it
+# would make every built extension report commitHash "unknown".
 node_modules
 .DS_Store
 dist

Makefile

@@ -11,7 +11,7 @@ setup:
 	@script/setup
 
 install:
-	@yarn install
+	@yarn install --frozen-lockfile
 
 test:
 	@script/test

README.md

@@ -31,10 +31,13 @@ list exists to detect symbol spoofing attacks and improve UX.
 ```bash
 git clone https://git.eeqj.de/sneak/autistmask.git
 cd autistmask
-make install
+make setup
 make build
 ```
 
+`make setup` is the entrypoint for a fresh clone: it installs dependencies from
+the lockfile and installs the git pre-commit hook.
+
 Load the extension:
 
 - **Chrome**: Navigate to `chrome://extensions/`, enable "Developer mode", click
@@ -97,6 +100,19 @@ provide:
 - `script/precommit` — run by the git pre-commit hook; runs `script/check`
 - `script/install-precommit` — install the git pre-commit hook
 
+The Makefile shims to those. It also carries a few targets that have no
+`script/` counterpart and are Makefile-only conveniences:
+
+- `make install` — `yarn install --frozen-lockfile` on its own, without the rest
+  of `script/bootstrap`. Frozen so a stale `yarn.lock` fails instead of being
+  silently rewritten. Use `make setup` for a fresh clone.
+- `make hooks` — shims to `script/install-precommit`
+- `make build` — build the extension into `dist/chrome/` and `dist/firefox/`
+- `make build-debug` — the same build with `AUTISTMASK_DEBUG=1` (see
+  [Debug Builds](#debug-builds))
+- `make clean` — remove `dist/`
+- `make dev` — build in watch mode
+
 ## End-to-End Tests
 
 `make test-e2e` builds `dist/chrome/` and drives the **real popup in a real
@@ -1173,8 +1189,8 @@ Currently supported:
 
 ### Testing
 
-- [ ] Tests for mnemonic generation and address derivation
-- [ ] Tests for xpub derivation and child address generation
+- [x] Tests for mnemonic generation and address derivation
+- [x] Tests for xpub derivation and child address generation
 - [ ] Test on Firefox (Manifest V2)
 
 ### Scam List

TODO.md

@@ -44,6 +44,19 @@ undefined identifiers, which is how
 
 # Completed Steps
 
+- 2026-08-11: Policy compliance sweep — conditional verbose test rerun, local
+  Tailwind binary instead of `npx`, `--frozen-lockfile` on `make install`, and
+  the Makefile-only targets documented in the README
+  ([#166](https://git.eeqj.de/sneak/AutistMask/issues/166)).
+- 2026-08-11: `script/verify-build` diagnostics corrected: the both-markers
+  message now states what is and is not proven, an unreadable bundle is
+  diagnosed as an I/O fault rather than as changed output, the `*.js` assumption
+  lives only in `build.js`, and the unlisted-bundle scan hard-fails when it
+  cannot enumerate `dist/`
+  ([#180](https://git.eeqj.de/sneak/AutistMask/issues/180)).
+- 2026-08-11: Known-answer test coverage for the crypto core — BIP-39/BIP-32
+  derivation in `wallet.js` and the Argon2id vault in `vault.js`
+  ([#159](https://git.eeqj.de/sneak/AutistMask/issues/159)).
 - 2026-08-11: Three `README.md` claims corrected against the code — blocklist
   attribution, token-display rule, navigation model
   ([#213](https://git.eeqj.de/sneak/AutistMask/issues/213)).
@@ -53,10 +66,18 @@ undefined identifiers, which is how
 - 2026-08-11: `docs/README.md` rewritten against the code: no competitor names,
   all five network destinations documented, password/Settings/Add Wallet
   sections corrected ([#163](https://git.eeqj.de/sneak/AutistMask/issues/163)).
+- 2026-08-11: `loadState()` now derives `hasWallet` from the wallet list instead
+  of trusting the persisted flag, so a profile already saved inconsistent no
+  longer stays broken on every load
+  ([#195](https://git.eeqj.de/sneak/AutistMask/issues/195)).
 - 2026-08-11: Wallet deletion repairs its own state — `hasWallet` follows the
   remaining wallets, the selection only moves when it was deleted, and the
   active-address change is broadcast to connected sites
   ([#156](https://git.eeqj.de/sneak/AutistMask/issues/156)).
+- 2026-08-11: One row per on-chain value movement in transaction history: the
+  merge moved into the pure `mergeTransactions` and the zero-ETH native side of
+  a plain ERC-20 transfer absorbed into its token row
+  ([#177](https://git.eeqj.de/sneak/AutistMask/issues/177)).
 - 2026-08-11: `TODO.md` Workflow rewritten to the branch-and-PR-per-issue model
   on `next`, with Status and Next Step refreshed
   ([#191](https://git.eeqj.de/sneak/AutistMask/issues/191)).

build.js

@@ -29,6 +29,12 @@ function repoRelative(p) {
 // reports every input that contributed to an output in the metafile, which is
 // the authoritative answer to "is constants.js in this bundle" — unlike
 // searching the minified text, it does not depend on what survived minification.
+//
+// The ".js" filter below is the only place that assumption lives:
+// script/verify-build searches every file and symlink under dist/ for a
+// marker, without filtering by extension, and hard-fails if it cannot walk the
+// whole tree, so a bundle emitted under some other extension fails there as
+// unlisted rather than escaping both checks at once.
 function outputsContainingAuditedModule(metafile) {
     return Object.entries(metafile.outputs)
         .filter(([outFile, info]) => {
@@ -115,8 +121,17 @@ async function build() {
     // build that never gets around to writing one cannot be verified against
     // a stale list.
     fs.rmSync(BUNDLE_MANIFEST, { force: true });
+    // The locally installed binary, not `npx` — npx silently fetches from the
+    // registry when the binary is absent, which is an unpinned network fetch
+    // in the middle of a build.
+    const tailwindBin = path.join(
+        __dirname,
+        "node_modules",
+        ".bin",
+        "tailwindcss",
+    );
     execSync(
-        `npx @tailwindcss/cli -i ${tailwindInput} -o ${tailwindOutput} --minify`,
+        `"${tailwindBin}" -i "${tailwindInput}" -o "${tailwindOutput}" --minify`,
         { stdio: "inherit" },
     );
 

package.json

@@ -7,6 +7,7 @@
     "private": true,
     "scripts": {
         "test": "jest --forceExit",
+        "test:verbose": "jest --forceExit --verbose",
         "build": "node build.js",
         "lint": "prettier --check .",
         "fmt": "prettier --write .",

script/test

@@ -7,7 +7,13 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 main() {
     cd "$ROOT"
     echo "Running tests..."
-    timeout 30 yarn run test 2>&1
+    timeout 30 yarn run test 2>&1 || {
+        echo "--- Rerunning with --verbose for details ---"
+        timeout 30 yarn run test:verbose 2>&1 || true
+        # Always fail: the first run already proved the tests are broken, so a
+        # flaky pass on the rerun must not turn the build green.
+        exit 1
+    }
 }
 
 main "$@"

script/verify-build

@@ -34,16 +34,51 @@ fail() {
     exit 1
 }
 
+# Is the literal $1 present in the file $2? Match (grep exit 0) and no-match
+# (exit 1) are answers about the emitted output. Anything else (exit 2: the
+# file could not be read) is not an answer at all, and must not be reported as
+# "no marker" — that would blame the bundle for a permissions or I/O fault.
 has_marker() {
-    grep -q -F "$1" "$2" 2>/dev/null
+    _hm_status=0
+    grep -q -F -e "$1" -- "$2" || _hm_status=$?
+    case "$_hm_status" in
+    0) return 0 ;;
+    1) return 1 ;;
+    *)
+        fail "grep exited $_hm_status reading $2, so the file could not be
+    searched and its DEBUG state was not checked at all. That is a permissions
+    or I/O fault on the artifact, not a change in the emitted output. Refusing
+    to report success."
+        ;;
+    esac
+}
+
+# Does the manifest list the path $1, as a whole line? Same discipline as
+# has_marker: exit 0 and 1 are answers about the manifest, exit 2 means the
+# manifest could not be read and is not an answer at all. Without this, an
+# unreadable manifest reads as "this file is not listed" and every emitted
+# bundle gets reported as an unlisted one.
+is_listed() {
+    _il_status=0
+    grep -q -x -F -e "$1" -- "$MANIFEST" || _il_status=$?
+    case "$_il_status" in
+    0) return 0 ;;
+    1) return 1 ;;
+    *)
+        fail "grep exited $_il_status reading $MANIFEST, so it could not be
+    searched and nothing was established about which bundles it lists. That is
+    a permissions or I/O fault on the manifest, not a stale manifest. Refusing
+    to report success."
+        ;;
+    esac
 }
 
 # Read one bundle's DEBUG state into MARKER. Exactly one marker must be
 # present. Both means the ternary in constants.js was never folded, which is
 # what happens when the __BUILD_DEBUG__ define goes missing from build.js:
-# DEBUG stops being known at build time and the debug branch is live again.
-# Neither means we are reading output we do not understand. Both are hard
-# failures; neither is ever treated as absence of a problem.
+# DEBUG stops being known at build time. Neither means we are reading output
+# we do not understand. Both are hard failures; neither is ever treated as
+# absence of a problem.
 read_marker() {
     _file="$1"
     _on=no
@@ -52,9 +87,14 @@ read_marker() {
     if has_marker "$MARKER_OFF" "$_file"; then _off=yes; fi
 
     if [ "$_on" = yes ] && [ "$_off" = yes ]; then
-        fail "$_file carries both debug markers, so the build-time DEBUG value
-    was never resolved and the debug branch is still live. Check that build.js
-    still defines __BUILD_DEBUG__."
+        fail "$_file carries both debug markers, so DEBUG was not resolved at
+    build time: the ternary in src/shared/constants.js survived into the
+    emitted output. This does not mean the debug branch is live in this
+    artifact: an unresolved __BUILD_DEBUG__ is undeclared in extension
+    context, so DEBUG evaluates to false at runtime. It does mean the
+    release/debug distinction is no longer enforced at build time, and which
+    way that fallback happens to evaluate is then an accident a refactor can
+    flip. Check that build.js still defines __BUILD_DEBUG__."
     fi
     if [ "$_on" = no ] && [ "$_off" = no ]; then
         fail "$_file carries no debug marker, so its DEBUG state cannot be
@@ -70,13 +110,43 @@ read_marker() {
 }
 
 # The manifest says which bundles must carry a marker. This says no other
-# emitted bundle may carry one, which catches a manifest that has gone stale
+# emitted file may carry one, which catches a manifest that has gone stale
 # or short rather than trusting whatever it happens to list.
+#
+# Deliberately unfiltered by extension. build.js selects manifest entries with
+# an endsWith(".js") test; repeating that literal here would mean a bundle
+# emitted under some other extension escaped the manifest AND this check at
+# once, which is the correlated blind spot the two-source design exists to
+# avoid. Every file under dist/ is searched, so build.js's filter is the only
+# place the assumption lives and this check is what catches it being wrong.
+#
+# That claim only holds if the walk is exhaustive, so two things are enforced
+# here rather than assumed:
+#
+#   - find's exit status is checked. A subtree it cannot descend is reported on
+#     stderr and then simply missing from the listing, so an unchecked status
+#     turns "could not look" into "nothing was there" — the same conflation
+#     has_marker exists to prevent. The status cannot be read off a pipeline
+#     ending in sort, so the sort is a separate step.
+#   - symlinks are walked too (-type l), not skipped. A marker-carrying bundle
+#     reachable under an unlisted path in dist/ is a stale manifest whether the
+#     path is a link or a file, and grep reads through the link. A link that
+#     cannot be read through — dangling, or pointing at a directory — fails
+#     hard via has_marker's exit-2 path, which is the fail-closed answer: the
+#     build emits neither, so their DEBUG state is unproven, not fine.
 check_unlisted_bundles() {
-    _listing="$(find dist -type f -name '*.js' | sort)"
+    _find_status=0
+    _listing="$(find dist \( -type f -o -type l \) -print)" || _find_status=$?
+    [ "$_find_status" -eq 0 ] ||
+        fail "find exited $_find_status enumerating dist/, so part of the tree
+    was never walked and nothing was established about the files in it. Any
+    unlisted bundle there went unchecked. That is a permissions or I/O fault on
+    the artifact, not a stale manifest. Refusing to report success."
+    _listing="$(printf '%s\n' "$_listing" | sort)"
+
     while read -r _file; do
         [ -n "$_file" ] || continue
-        if grep -q -x -F "$_file" "$MANIFEST"; then
+        if is_listed "$_file"; then
             continue
         fi
         if has_marker "$MARKER_ON" "$_file" ||
@@ -113,12 +183,18 @@ main() {
         fail "$MANIFEST is empty, so no emitted bundle was found to contain
     src/shared/constants.js. That is never correct, so it is a failure and not
     a pass."
+    [ -r "$MANIFEST" ] ||
+        fail "$MANIFEST is not readable, so nothing was inspected. That is a
+    permissions or I/O fault, not a pass."
 
     count=0
     while read -r file; do
         [ -n "$file" ] || continue
         [ -f "$file" ] ||
             fail "$MANIFEST lists $file, which does not exist."
+        [ -s "$file" ] ||
+            fail "$MANIFEST lists $file, which is empty. An empty bundle
+    carries no marker and proves nothing, so this is a failure and not a pass."
         read_marker "$file"
         [ "$MARKER" = "$expected" ] ||
             fail "$file is $MARKER but this build expects $expected."

src/shared/state.js

@@ -84,8 +84,11 @@ async function loadState() {
     const result = await storageApi.get("autistmask");
     if (result.autistmask) {
         const saved = result.autistmask;
-        state.hasWallet = saved.hasWallet;
         state.wallets = saved.wallets || [];
+        // Derived, never read from storage: a profile persisted with the flag
+        // out of step with the wallet list would otherwise stay broken on
+        // every load. Nothing depends on the two disagreeing.
+        state.hasWallet = state.wallets.length > 0;
         state.trackedTokens = saved.trackedTokens || [];
         state.networkId = saved.networkId || DEFAULT_STATE.networkId;
         state.rpcUrl = saved.rpcUrl || DEFAULT_STATE.rpcUrl;

src/shared/transactions.js

@@ -113,6 +113,85 @@ function parseTokenTransfer(tt, addrLower) {
     };
 }
 
+// True when a parsed native entry moved no ETH.  Contract-call entries have
+// their amount fields blanked by parseTx, so they are never judged here.
+function movedNoEther(tx) {
+    if (tx.direction === "contract") return false;
+    return BigInt(tx.rawAmount || "0") === BigInt(0);
+}
+
+// Merge parsed normal transactions with parsed ERC-20 token transfers into
+// one row per distinct value movement.  Pure: it reads only its arguments
+// and returns a new list sorted newest block first.
+//
+// The merge key is the transaction hash for the native entry and
+// hash + token contract for each token transfer, so:
+//
+//   - A display-level contract call (a swap and friends, direction
+//     "contract") absorbs every token leg of its hash into the single
+//     native entry, because the legs are hops of one operation rather
+//     than separate movements the user made.
+//   - Otherwise each distinct token contract in the transaction keeps its
+//     own row, so a hash carrying several genuine transfers stays several
+//     rows.
+//   - The native entry of such a transaction is dropped when it moved no
+//     ETH and at least one token transfer shares its hash: that entry is
+//     the ERC-20 call itself, already represented by the token row.  A
+//     native entry that moved ETH survives alongside the token rows, since
+//     the ETH and the tokens are two real movements, and a zero-value
+//     native transaction with no token transfer on its hash survives too.
+function mergeTransactions(txs, tokenTransfers) {
+    const byKey = new Map();
+
+    // Entries are copied so consolidation never writes through to the
+    // caller's objects.
+    for (const tx of txs) {
+        byKey.set(tx.hash, { ...tx });
+    }
+
+    const absorbedHashes = new Set();
+
+    for (const parsed of tokenTransfers) {
+        const existing = byKey.get(parsed.hash);
+        if (existing && existing.direction === "contract") {
+            // For contract calls (swaps), consolidate into the original
+            // tx entry.  Prefer the "received" transfer (swap output)
+            // for the display amount.  If no received transfer exists,
+            // fall back to the first "sent" transfer (swap input).
+            const isReceived = parsed.direction === "received";
+            const needsAmount = !existing.exactValue;
+            if (isReceived || needsAmount) {
+                existing.value = parsed.value;
+                existing.exactValue = parsed.exactValue;
+                existing.rawAmount = parsed.rawAmount;
+                existing.rawUnit = parsed.rawUnit;
+                existing.symbol = parsed.symbol;
+                existing.contractAddress = parsed.contractAddress;
+                existing.holders = parsed.holders;
+            }
+            // Keep the original tx's from/to (the user's address and the
+            // contract they called), not the token transfer's from/to
+            // which may be a router or Permit2 contract.
+            continue;
+        }
+        if (existing && movedNoEther(existing)) {
+            absorbedHashes.add(parsed.hash);
+        }
+        // Every other token transfer gets its own entry.
+        byKey.set(parsed.hash + ":" + (parsed.contractAddress || ""), {
+            ...parsed,
+        });
+    }
+
+    for (const hash of absorbedHashes) {
+        byKey.delete(hash);
+    }
+
+    const merged = [...byKey.values()];
+    merged.sort((a, b) => b.blockNumber - a.blockNumber);
+    return merged;
+}
+
 async function fetchRecentTransactions(address, blockscoutUrl, count = 25) {
     log.debugf("fetchRecentTransactions", address);
     const addrLower = address.toLowerCase();
@@ -145,53 +224,11 @@ async function fetchRecentTransactions(address, blockscoutUrl, count = 25) {
     const txJson = txResp.ok ? await txResp.json() : {};
     const ttJson = ttResp.ok ? await ttResp.json() : {};
 
-    const txsByHash = new Map();
+    const txs = mergeTransactions(
+        (txJson.items || []).map((tx) => parseTx(tx, addrLower)),
+        (ttJson.items || []).map((tt) => parseTokenTransfer(tt, addrLower)),
+    );
 
-    for (const tx of txJson.items || []) {
-        txsByHash.set(tx.hash, parseTx(tx, addrLower));
-    }
-
-    // When a token transfer shares a hash with a normal tx, the normal tx
-    // is the contract call (0 ETH) and the token transfer has the real
-    // amount and symbol.  For contract calls (swaps), a single transaction
-    // can produce multiple token transfers (input, intermediates, output).
-    // We consolidate these into the original tx entry using the token
-    // transfer where the user *receives* tokens (the swap output), so
-    // the transaction list shows the final result rather than confusing
-    // intermediate hops.  We preserve the original tx's from/to so the
-    // user sees their own address, not a router or Permit2 contract.
-    for (const tt of ttJson.items || []) {
-        const parsed = parseTokenTransfer(tt, addrLower);
-        const existing = txsByHash.get(parsed.hash);
-        if (existing && existing.direction === "contract") {
-            // For contract calls (swaps), consolidate into the original
-            // tx entry.  Prefer the "received" transfer (swap output)
-            // for the display amount.  If no received transfer exists,
-            // fall back to the first "sent" transfer (swap input).
-            const isReceived = parsed.direction === "received";
-            const needsAmount = !existing.exactValue;
-            if (isReceived || needsAmount) {
-                existing.value = parsed.value;
-                existing.exactValue = parsed.exactValue;
-                existing.rawAmount = parsed.rawAmount;
-                existing.rawUnit = parsed.rawUnit;
-                existing.symbol = parsed.symbol;
-                existing.contractAddress = parsed.contractAddress;
-                existing.holders = parsed.holders;
-            }
-            // Keep the original tx's from/to (the user's address and the
-            // contract they called), not the token transfer's from/to
-            // which may be a router or Permit2 contract.
-            continue;
-        }
-        // Non-contract token transfers get their own entries.
-        const ttKey = parsed.hash + ":" + (parsed.contractAddress || "");
-        txsByHash.set(ttKey, parsed);
-    }
-
-    const txs = [...txsByHash.values()];
-
-    txs.sort((a, b) => b.blockNumber - a.blockNumber);
     const result = txs.slice(0, count);
     log.debugf("fetchRecentTransactions done, count:", result.length);
     return result;
@@ -265,4 +302,8 @@ function filterTransactions(txs, filters = {}) {
     return { transactions: filtered, newFraudContracts: newFraud };
 }
 
-module.exports = { fetchRecentTransactions, filterTransactions };
+module.exports = {
+    fetchRecentTransactions,
+    filterTransactions,
+    mergeTransactions,
+};

tests/state.test.js

@@ -0,0 +1,104 @@
+const ADDRESS = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
+
+function oneWallet() {
+    return [{ name: "Wallet 1", type: "hd", addresses: [ADDRESS] }];
+}
+
+// state.js resolves the storage API at require time, so the stub has to exist
+// before the module is loaded, and the module registry has to be reset between
+// cases because `state` is a module-level singleton.
+function loadModuleWith(persisted) {
+    jest.resetModules();
+    const set = jest.fn(async () => {});
+    global.chrome = {
+        storage: {
+            local: {
+                get: jest.fn(async () =>
+                    persisted ? { autistmask: persisted } : {},
+                ),
+                set,
+            },
+        },
+    };
+    return { mod: require("../src/shared/state"), set };
+}
+
+afterEach(() => {
+    delete global.chrome;
+});
+
+describe("loadState hasWallet reconciliation", () => {
+    // A profile that deleted its last wallet on a build predating the write
+    // path fix keeps hasWallet: true forever. It must load as no wallet, which
+    // is what sends the popup to the welcome view.
+    test("stored hasWallet true with zero wallets loads as no wallet", async () => {
+        const { mod } = loadModuleWith({ hasWallet: true, wallets: [] });
+        await mod.loadState();
+        expect(mod.state.hasWallet).toBe(false);
+    });
+
+    test("stored hasWallet true with a missing wallets key loads as no wallet", async () => {
+        const { mod } = loadModuleWith({ hasWallet: true });
+        await mod.loadState();
+        expect(mod.state.wallets).toEqual([]);
+        expect(mod.state.hasWallet).toBe(false);
+    });
+
+    test("stored hasWallet false with one wallet loads as having a wallet", async () => {
+        const { mod } = loadModuleWith({
+            hasWallet: false,
+            wallets: oneWallet(),
+        });
+        await mod.loadState();
+        expect(mod.state.hasWallet).toBe(true);
+    });
+
+    test("absent hasWallet with wallets present loads as having a wallet", async () => {
+        const { mod } = loadModuleWith({ wallets: oneWallet() });
+        await mod.loadState();
+        expect(mod.state.hasWallet).toBe(true);
+    });
+
+    test("consistent stored states are preserved", async () => {
+        const withWallet = loadModuleWith({
+            hasWallet: true,
+            wallets: oneWallet(),
+        });
+        await withWallet.mod.loadState();
+        expect(withWallet.mod.state.hasWallet).toBe(true);
+
+        const without = loadModuleWith({ hasWallet: false, wallets: [] });
+        await without.mod.loadState();
+        expect(without.mod.state.hasWallet).toBe(false);
+    });
+
+    test("empty storage leaves the default no-wallet state", async () => {
+        const { mod } = loadModuleWith(null);
+        await mod.loadState();
+        expect(mod.state.hasWallet).toBe(false);
+        expect(mod.state.wallets).toEqual([]);
+    });
+
+    // The correction is derived on every load rather than written back, so a
+    // load never has a storage side effect.
+    test("loadState does not write to storage", async () => {
+        const { mod, set } = loadModuleWith({ hasWallet: true, wallets: [] });
+        await mod.loadState();
+        expect(set).not.toHaveBeenCalled();
+    });
+
+    // Deriving must not disturb the rest of the load.
+    test("other persisted fields still load", async () => {
+        const { mod } = loadModuleWith({
+            hasWallet: false,
+            wallets: oneWallet(),
+            networkId: "sepolia",
+            theme: "dark",
+            activeAddress: ADDRESS,
+        });
+        await mod.loadState();
+        expect(mod.state.networkId).toBe("sepolia");
+        expect(mod.state.theme).toBe("dark");
+        expect(mod.state.activeAddress).toBe(ADDRESS);
+    });
+});

tests/transactions.test.js

@@ -36,6 +36,7 @@ global.chrome = { storage: { local: {} } };
 const {
     fetchRecentTransactions,
     filterTransactions,
+    mergeTransactions,
 } = require("../src/shared/transactions");
 const { KNOWN_SYMBOLS } = require("../src/shared/tokenList");
 const { debugFetch } = require("../src/shared/log");
@@ -685,6 +686,339 @@ describe("legitimate transactions are never filtered", () => {
     });
 });
 
+// ---------------------------------------------------------------------------
+// mergeTransactions is the pure core of the merge: it takes parsed native
+// entries and parsed token transfers and decides how many rows one on-chain
+// transaction becomes.  One transaction is one row per distinct value
+// movement, so the native side of a plain ERC-20 transfer must not survive
+// next to its token row (the duplicate-row bug), while a hash that really
+// did move several things must keep a row for each.
+// ---------------------------------------------------------------------------
+
+// A native entry as parseTx produces it for a decoded contract call: the
+// amount fields are blanked and direction is "contract".
+function contractCallTx(overrides = {}) {
+    return nativeTx({
+        from: VICTIM,
+        to: USDC_CONTRACT,
+        value: "",
+        exactValue: "",
+        rawAmount: "",
+        rawUnit: "",
+        valueGwei: 0,
+        direction: "contract",
+        directionLabel: "Approve",
+        isContractCall: true,
+        method: "approve",
+        ...overrides,
+    });
+}
+
+// The native entry parseTx produces for a plain ERC-20 transfer: sent to the
+// token contract, no ETH, and method "transfer", which is exactly why it is
+// not marked as a display-level contract call.
+function erc20CallTx(overrides = {}) {
+    return nativeTx({
+        from: VICTIM,
+        to: USDC_CONTRACT,
+        value: "0.0000",
+        exactValue: "0.0",
+        rawAmount: "0",
+        valueGwei: 0,
+        direction: "sent",
+        directionLabel: "Sent",
+        isContractCall: true,
+        method: "transfer",
+        ...overrides,
+    });
+}
+
+describe("mergeTransactions: one row per value movement", () => {
+    const HASH = "0x" + "d".repeat(64);
+    const OTHER_HASH = "0x" + "e".repeat(64);
+    const ROUTER = "0x3fc91a3afd70395cd496c647d5a6cc9d4b2b7fad";
+
+    test("a plain ERC-20 transfer yields one row, the token row", () => {
+        const native = erc20CallTx({ hash: HASH });
+        const token = tokenTx({
+            hash: HASH,
+            from: VICTIM,
+            to: ORDINARY_PEER,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+
+        const merged = mergeTransactions([native], [token]);
+        expect(merged).toHaveLength(1);
+        expect(merged[0].symbol).toBe("USDC");
+        expect(merged[0].exactValue).toBe("1500.5");
+        expect(merged[0].contractAddress).toBe(USDC_CONTRACT);
+    });
+
+    test("an ETH-only transfer keeps its row unchanged", () => {
+        const merged = mergeTransactions([legitimateEthSend()], []);
+        expect(merged).toHaveLength(1);
+        expect(merged[0]).toEqual(legitimateEthSend());
+    });
+
+    test("a genuine zero-value native transaction is still displayed", () => {
+        const zero = nativeTx({
+            hash: HASH,
+            from: VICTIM,
+            to: ORDINARY_PEER,
+            value: "0.0000",
+            exactValue: "0.0",
+            rawAmount: "0",
+            valueGwei: 0,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+
+        const merged = mergeTransactions([zero], []);
+        expect(merged).toEqual([zero]);
+    });
+
+    test("a zero-value native row is only absorbed by a transfer sharing its hash", () => {
+        const zero = erc20CallTx({ hash: HASH });
+        const unrelated = tokenTx({ hash: OTHER_HASH });
+
+        const merged = mergeTransactions([zero], [unrelated]);
+        expect(merged).toHaveLength(2);
+        expect(merged.map((t) => t.hash).sort()).toEqual(
+            [HASH, OTHER_HASH].sort(),
+        );
+    });
+
+    test("a native transaction that moved ETH keeps its row beside the token row", () => {
+        // An undecoded call (no method name) carrying ETH that also emitted
+        // a token transfer: two real movements, so two rows.
+        const native = nativeTx({
+            hash: HASH,
+            from: VICTIM,
+            to: ROUTER,
+            value: "0.2500",
+            exactValue: "0.25",
+            rawAmount: "250000000000000000",
+            valueGwei: 250000000,
+            direction: "sent",
+            directionLabel: "Sent",
+            isContractCall: true,
+        });
+        const token = tokenTx({ hash: HASH, from: ROUTER, to: VICTIM });
+
+        const merged = mergeTransactions([native], [token]);
+        expect(merged).toHaveLength(2);
+        expect(merged.map((t) => t.symbol).sort()).toEqual(["ETH", "USDC"]);
+    });
+
+    test("a sub-gwei ETH movement keeps its row beside the token row", () => {
+        // 500000000 wei is 0.5 gwei, so parseTx's valueGwei floors to 0 while
+        // rawAmount stays nonzero.  Deciding "moved no ETH" on valueGwei would
+        // delete this row and lose a real ETH movement, so the decision is made
+        // on rawAmount as a BigInt.
+        const native = nativeTx({
+            hash: HASH,
+            from: VICTIM,
+            to: ROUTER,
+            value: "0.0000",
+            exactValue: "0.0000000005",
+            rawAmount: "500000000",
+            valueGwei: 0,
+            direction: "sent",
+            directionLabel: "Sent",
+            isContractCall: true,
+        });
+        const token = tokenTx({ hash: HASH, from: ROUTER, to: VICTIM });
+
+        const merged = mergeTransactions([native], [token]);
+        expect(merged).toHaveLength(2);
+        expect(merged.map((t) => t.symbol).sort()).toEqual(["ETH", "USDC"]);
+        expect(merged.find((t) => t.symbol === "ETH").rawAmount).toBe(
+            "500000000",
+        );
+    });
+
+    test("a swap consolidates every token leg into one row, preferring the received leg", () => {
+        const native = contractCallTx({
+            hash: HASH,
+            to: ROUTER,
+            directionLabel: "Swap",
+            method: "execute",
+        });
+        const sentLeg = tokenTx({
+            hash: HASH,
+            from: VICTIM,
+            to: ROUTER,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+        const receivedLeg = tokenTx({
+            hash: HASH,
+            from: ROUTER,
+            to: VICTIM,
+            value: "0.2500",
+            exactValue: "0.25",
+            rawAmount: "250000000000000000",
+            rawUnit: "WETH base units (10^-18)",
+            symbol: "WETH",
+            contractAddress: WETH_CONTRACT,
+            holders: 850000,
+        });
+
+        const merged = mergeTransactions([native], [sentLeg, receivedLeg]);
+        expect(merged).toHaveLength(1);
+        expect(merged[0].symbol).toBe("WETH");
+        expect(merged[0].exactValue).toBe("0.25");
+        // The user's own address and the contract called are preserved.
+        expect(merged[0].from).toBe(VICTIM);
+        expect(merged[0].to).toBe(ROUTER);
+        expect(merged[0].directionLabel).toBe("Swap");
+    });
+
+    test("a swap whose legs are all sent takes its amount from the first sent leg", () => {
+        const native = contractCallTx({
+            hash: HASH,
+            to: ROUTER,
+            directionLabel: "Swap",
+            method: "execute",
+        });
+        const firstSent = tokenTx({
+            hash: HASH,
+            from: VICTIM,
+            to: ROUTER,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+        const secondSent = tokenTx({
+            hash: HASH,
+            from: VICTIM,
+            to: ROUTER,
+            value: "0.2500",
+            exactValue: "0.25",
+            rawAmount: "250000000000000000",
+            rawUnit: "WETH base units (10^-18)",
+            symbol: "WETH",
+            contractAddress: WETH_CONTRACT,
+            holders: 850000,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+
+        const merged = mergeTransactions([native], [firstSent, secondSent]);
+        expect(merged).toHaveLength(1);
+        // With no received leg the display amount comes from the first sent
+        // leg, and a later sent leg does not overwrite it.
+        expect(merged[0].symbol).toBe("USDC");
+        expect(merged[0].exactValue).toBe("1500.5");
+        expect(merged[0].contractAddress).toBe(USDC_CONTRACT);
+        expect(merged[0].holders).toBe(3500000);
+    });
+
+    test("a contract call carrying ETH plus a token transfer stays one row", () => {
+        const native = contractCallTx({
+            hash: HASH,
+            to: ROUTER,
+            directionLabel: "Swap",
+            method: "swapExactETHForTokens",
+            valueGwei: 250000000,
+        });
+        const received = tokenTx({ hash: HASH, from: ROUTER, to: VICTIM });
+
+        const merged = mergeTransactions([native], [received]);
+        expect(merged).toHaveLength(1);
+        expect(merged[0].symbol).toBe("USDC");
+        expect(merged[0].exactValue).toBe("1500.5");
+        // The ETH leg is still visible as the row's native quantity.
+        expect(merged[0].valueGwei).toBe(250000000);
+    });
+
+    test("an approve keeps its row and survives the filters", () => {
+        const approve = contractCallTx({ hash: HASH });
+
+        const merged = mergeTransactions([approve], []);
+        expect(merged).toEqual([approve]);
+        expect(filterTransactions(merged, filters()).transactions).toEqual([
+            approve,
+        ]);
+    });
+
+    test("a contract creation keeps its row", () => {
+        const creation = nativeTx({
+            hash: HASH,
+            from: VICTIM,
+            to: "",
+            value: "0.0000",
+            exactValue: "0.0",
+            rawAmount: "0",
+            valueGwei: 0,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+
+        expect(mergeTransactions([creation], [])).toEqual([creation]);
+    });
+
+    test("a native self-send keeps its single row", () => {
+        const selfSend = nativeTx({
+            hash: HASH,
+            from: VICTIM,
+            to: VICTIM,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+
+        expect(mergeTransactions([selfSend], [])).toEqual([selfSend]);
+    });
+
+    test("a token self-send yields one row", () => {
+        const native = erc20CallTx({ hash: HASH });
+        const token = tokenTx({
+            hash: HASH,
+            from: VICTIM,
+            to: VICTIM,
+            direction: "sent",
+            directionLabel: "Sent",
+        });
+
+        const merged = mergeTransactions([native], [token]);
+        expect(merged).toHaveLength(1);
+        expect(merged[0].symbol).toBe("USDC");
+        expect(merged[0].from).toBe(VICTIM);
+        expect(merged[0].to).toBe(VICTIM);
+    });
+
+    test("several distinct tokens moved by one ERC-20 call keep a row each", () => {
+        const native = erc20CallTx({ hash: HASH });
+        const usdc = tokenTx({ hash: HASH });
+        const weth = tokenTx({
+            hash: HASH,
+            symbol: "WETH",
+            contractAddress: WETH_CONTRACT,
+            holders: 850000,
+        });
+
+        const merged = mergeTransactions([native], [usdc, weth]);
+        expect(merged.map((t) => t.symbol).sort()).toEqual(["USDC", "WETH"]);
+    });
+
+    test("rows are sorted by block number, newest first", () => {
+        const older = nativeTx({ hash: HASH, blockNumber: 21000000 });
+        const newer = nativeTx({ hash: OTHER_HASH, blockNumber: 21000010 });
+
+        const merged = mergeTransactions([older, newer], []);
+        expect(merged.map((t) => t.blockNumber)).toEqual([21000010, 21000000]);
+    });
+
+    test("the entries handed in are never mutated", () => {
+        const native = contractCallTx({ hash: HASH, method: "execute" });
+        const token = tokenTx({ hash: HASH });
+        const before = JSON.stringify([native, token]);
+
+        mergeTransactions([native], [token]);
+        expect(JSON.stringify([native, token])).toBe(before);
+    });
+});
+
 // ---------------------------------------------------------------------------
 // fetchRecentTransactions owns the per-address merge of normal transactions
 // with ERC-20 transfers.  (The cross-address merge Home performs lives in
@@ -886,13 +1220,12 @@ describe("fetchRecentTransactions merge and dedup", () => {
         expect(txs.map((t) => t.symbol).sort()).toEqual(["USDC", "WETH"]);
     });
 
-    // Documents current behaviour: for a plain ERC-20 transfer the method is
-    // "transfer", so parseTx does not mark the entry as a contract call in
-    // the display sense and the merge loop does not consolidate the token
-    // transfer into it.  The result is two entries for one transaction: a
-    // zero-value native row and the real token row.  The zero-value row also
-    // escapes dust filtering because isContractCall is true.
-    test("current behaviour: a plain ERC-20 transfer produces two entries", async () => {
+    // Regression guard for the duplicate-row bug: for a plain ERC-20
+    // transfer the method is "transfer", so parseTx does not mark the entry
+    // as a contract call in the display sense.  The native side of that
+    // transaction moved no ETH and is represented by the token row, so it
+    // must not survive the merge as a second, zero-value row.
+    test("a plain ERC-20 transfer produces exactly one entry", async () => {
         const hash = "0x" + "5".repeat(64);
         respondWith(
             [
@@ -925,14 +1258,15 @@ describe("fetchRecentTransactions merge and dedup", () => {
         );
 
         const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT);
-        expect(txs).toHaveLength(2);
-        expect(txs.map((t) => t.symbol).sort()).toEqual(["ETH", "USDC"]);
-        const nativeRow = txs.find((t) => t.symbol === "ETH");
-        expect(nativeRow.exactValue).toBe("0.0");
-        expect(nativeRow.isContractCall).toBe(true);
-        // And the zero-value row is not removed by the dust filter.
+        expect(txs).toHaveLength(1);
+        expect(txs[0].symbol).toBe("USDC");
+        expect(txs[0].exactValue).toBe("1.0");
+        expect(txs[0].direction).toBe("sent");
+        expect(txs[0].contractAddress).toBe(USDC_CONTRACT);
+        // The surviving row is the token row, and the filters keep it.
         const kept = filterTransactions(txs, filters()).transactions;
-        expect(kept).toHaveLength(2);
+        expect(kept).toHaveLength(1);
+        expect(kept[0].symbol).toBe("USDC");
     });
 
     test("entries are sorted by block number descending and capped at count", async () => {

tests/vault.test.js

@@ -0,0 +1,346 @@
+// Tests for src/shared/vault.js: the Argon2id + XSalsa20-Poly1305 encryption
+// that protects recovery phrases and private keys at rest.
+//
+// The properties that matter here are the ones whose failure is silent. A
+// vault that decrypts under the wrong password, that hands back plaintext from
+// a ciphertext an attacker edited, that reuses a nonce, or that leaves the
+// recovery phrase readable somewhere in the stored blob all look exactly like
+// a working vault from the UI. So each test below asserts a negative: the
+// thing that must not happen.
+//
+// Cost: every encrypt and decrypt runs one Argon2id pwhash at the production
+// interactive parameters, which the module hardcodes. The parameters are not
+// weakened or overridden anywhere in this file — they are pinned by the "key
+// derivation cost" tests, since they are the vault's only defence against an
+// offline attack on a stolen blob. The suite is kept inside script/test's
+// 30-second budget by sharing one encrypted fixture across the tamper cases
+// instead of re-encrypting per test.
+
+const sodium = require("libsodium-wrappers-sumo");
+const {
+    encryptWithPassword,
+    decryptWithPassword,
+} = require("../src/shared/vault");
+
+// A publicly known development phrase. Never fund it.
+const SECRET = "test test test test test test test test test test test junk";
+const PASSWORD = "correct horse battery staple";
+const WRONG_PASSWORD = "correct horse battery stapl";
+
+const SALT_BYTES = 16;
+const NONCE_BYTES = 24;
+const POLY1305_TAG_BYTES = 16;
+
+const BASE64 = /^[A-Za-z0-9+/_-]+={0,2}$/;
+
+function b64decode(s) {
+    return sodium.from_base64(s);
+}
+
+// A shallow copy with one field replaced, so the shared fixture is never
+// mutated by a tamper test.
+function withField(blob, field, value) {
+    return { ...blob, [field]: value };
+}
+
+// Flip the low bit of one byte of a base64-encoded field.
+function flipByte(b64, index) {
+    const bytes = b64decode(b64);
+    bytes[index] ^= 0x01;
+    return sodium.to_base64(bytes);
+}
+
+let vault;
+
+beforeAll(async () => {
+    await sodium.ready;
+    vault = await encryptWithPassword(SECRET, PASSWORD);
+});
+
+describe("stored blob shape", () => {
+    test("is exactly the documented { salt, nonce, ciphertext }", () => {
+        expect(Object.keys(vault).sort()).toEqual([
+            "ciphertext",
+            "nonce",
+            "salt",
+        ]);
+    });
+
+    test("every field is a base64 string", () => {
+        for (const field of ["salt", "nonce", "ciphertext"]) {
+            expect(typeof vault[field]).toBe("string");
+            expect(vault[field]).toMatch(BASE64);
+        }
+    });
+
+    test("salt and nonce are full length", () => {
+        expect(b64decode(vault.salt)).toHaveLength(SALT_BYTES);
+        expect(b64decode(vault.nonce)).toHaveLength(NONCE_BYTES);
+    });
+
+    test("ciphertext carries a Poly1305 authentication tag", () => {
+        expect(b64decode(vault.ciphertext)).toHaveLength(
+            SECRET.length + POLY1305_TAG_BYTES,
+        );
+    });
+
+    test("the blob survives JSON storage unchanged", async () => {
+        const stored = JSON.parse(JSON.stringify(vault));
+
+        await expect(decryptWithPassword(stored, PASSWORD)).resolves.toBe(
+            SECRET,
+        );
+    });
+});
+
+describe("no plaintext leakage", () => {
+    test("the secret does not appear in the serialized vault", () => {
+        const serialized = JSON.stringify(vault);
+
+        expect(serialized).not.toContain(SECRET);
+        for (const word of new Set(SECRET.split(" "))) {
+            expect(serialized).not.toContain(word);
+        }
+    });
+
+    test("the ciphertext bytes do not contain the secret bytes", () => {
+        const bytes = Buffer.from(b64decode(vault.ciphertext));
+
+        expect(bytes.includes(Buffer.from(SECRET, "utf8"))).toBe(false);
+        // Not even the first word, which would betray an unencrypted prefix.
+        expect(bytes.includes(Buffer.from("test test", "utf8"))).toBe(false);
+    });
+
+    test("the password does not appear in the serialized vault", () => {
+        expect(JSON.stringify(vault)).not.toContain(PASSWORD);
+    });
+});
+
+describe("round trip", () => {
+    test("decrypts back to the original secret", async () => {
+        await expect(decryptWithPassword(vault, PASSWORD)).resolves.toBe(
+            SECRET,
+        );
+    });
+
+    test("survives a non-ASCII plaintext byte for byte", async () => {
+        const unicode = "recovery phrase é中文\u{1f600}";
+
+        const blob = await encryptWithPassword(unicode, PASSWORD);
+
+        await expect(decryptWithPassword(blob, PASSWORD)).resolves.toBe(
+            unicode,
+        );
+    });
+
+    test("an empty password still round-trips and is not a bypass", async () => {
+        const blob = await encryptWithPassword(SECRET, "");
+
+        await expect(decryptWithPassword(blob, "")).resolves.toBe(SECRET);
+        // An empty password must not act as a skeleton key on other vaults,
+        // nor may a real password open an empty-password vault.
+        await expect(decryptWithPassword(vault, "")).rejects.toThrow();
+        await expect(decryptWithPassword(blob, PASSWORD)).rejects.toThrow();
+    });
+});
+
+describe("fresh salt and nonce", () => {
+    test("two encryptions of the same plaintext differ in all three fields", async () => {
+        const second = await encryptWithPassword(SECRET, PASSWORD);
+
+        expect(second.salt).not.toBe(vault.salt);
+        expect(second.nonce).not.toBe(vault.nonce);
+        expect(second.ciphertext).not.toBe(vault.ciphertext);
+        await expect(decryptWithPassword(second, PASSWORD)).resolves.toBe(
+            SECRET,
+        );
+    });
+});
+
+describe("key derivation cost", () => {
+    // Argon2id's opslimit and memlimit are the whole of the vault's resistance
+    // to an offline attack on a stolen blob, and lowering them breaks nothing
+    // any other test here can see — the suite merely runs faster. So pin them
+    // directly, both to libsodium's INTERACTIVE constants and to the absolute
+    // values those constants must keep meaning.
+    const INTERACTIVE_OPSLIMIT = 2;
+    const INTERACTIVE_MEMLIMIT = 64 * 1024 * 1024;
+
+    test("the interactive constants still mean 2 passes over 64 MiB", () => {
+        expect(sodium.crypto_pwhash_OPSLIMIT_INTERACTIVE).toBe(
+            INTERACTIVE_OPSLIMIT,
+        );
+        expect(sodium.crypto_pwhash_MEMLIMIT_INTERACTIVE).toBe(
+            INTERACTIVE_MEMLIMIT,
+        );
+        // The floor these must never quietly be swapped for: _MIN is one pass
+        // over 8 KiB, an 8192x reduction in memory cost.
+        expect(sodium.crypto_pwhash_OPSLIMIT_MIN).toBeLessThan(
+            INTERACTIVE_OPSLIMIT,
+        );
+        expect(sodium.crypto_pwhash_MEMLIMIT_MIN).toBeLessThan(
+            INTERACTIVE_MEMLIMIT,
+        );
+    });
+
+    test("a key derived at the interactive parameters opens the vault", () => {
+        // Independent of any spy, and of the module's own code path: derive
+        // the key here from the vault's published salt at the interactive cost
+        // and open its ciphertext directly. A vault whose key came from any
+        // other opslimit, memlimit or Argon2id variant yields a different key
+        // and cannot be opened this way.
+        const key = sodium.crypto_pwhash(
+            sodium.crypto_secretbox_KEYBYTES,
+            PASSWORD,
+            b64decode(vault.salt),
+            INTERACTIVE_OPSLIMIT,
+            INTERACTIVE_MEMLIMIT,
+            sodium.crypto_pwhash_ALG_ARGON2ID13,
+        );
+        const opened = sodium.crypto_secretbox_open_easy(
+            b64decode(vault.ciphertext),
+            b64decode(vault.nonce),
+            key,
+        );
+
+        expect(sodium.to_string(opened)).toBe(SECRET);
+    });
+
+    test.each([
+        [
+            "encrypt",
+            async () => {
+                await encryptWithPassword(SECRET, PASSWORD);
+            },
+        ],
+        [
+            "decrypt",
+            async () => {
+                await decryptWithPassword(vault, PASSWORD);
+            },
+        ],
+    ])("%s derives exactly one key at the interactive cost", async (_, run) => {
+        const spy = jest.spyOn(sodium, "crypto_pwhash");
+        try {
+            await run();
+
+            expect(spy).toHaveBeenCalledTimes(1);
+            const [keyBytes, , salt, opslimit, memlimit, alg] =
+                spy.mock.calls[0];
+            expect(keyBytes).toBe(sodium.crypto_secretbox_KEYBYTES);
+            expect(salt).toHaveLength(SALT_BYTES);
+            expect(opslimit).toBe(sodium.crypto_pwhash_OPSLIMIT_INTERACTIVE);
+            expect(memlimit).toBe(sodium.crypto_pwhash_MEMLIMIT_INTERACTIVE);
+            expect(alg).toBe(sodium.crypto_pwhash_ALG_ARGON2ID13);
+        } finally {
+            spy.mockRestore();
+        }
+    });
+});
+
+describe("wrong password", () => {
+    test("is rejected, and rejects cleanly", async () => {
+        // rejects.toThrow asserts a rejected promise, not a synchronous throw
+        // and not an unhandled rejection: the caller can catch this.
+        await expect(
+            decryptWithPassword(vault, WRONG_PASSWORD),
+        ).rejects.toThrow();
+    });
+
+    test("returns no plaintext, not even partially", async () => {
+        const result = await decryptWithPassword(vault, WRONG_PASSWORD).catch(
+            (err) => err,
+        );
+
+        expect(result).toBeInstanceOf(Error);
+        expect(String(result)).not.toContain("test");
+    });
+
+    test("the empty password is rejected on a password-protected vault", async () => {
+        await expect(decryptWithPassword(vault, "")).rejects.toThrow();
+    });
+});
+
+describe("tampering", () => {
+    test("a flipped ciphertext bit is rejected by the auth tag", async () => {
+        const tampered = withField(
+            vault,
+            "ciphertext",
+            flipByte(vault.ciphertext, 0),
+        );
+
+        await expect(decryptWithPassword(tampered, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a flipped bit in the authentication tag itself is rejected", async () => {
+        const tagStart = b64decode(vault.ciphertext).length - 1;
+        const tampered = withField(
+            vault,
+            "ciphertext",
+            flipByte(vault.ciphertext, tagStart),
+        );
+
+        await expect(decryptWithPassword(tampered, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a flipped nonce bit is rejected", async () => {
+        const tampered = withField(vault, "nonce", flipByte(vault.nonce, 0));
+
+        await expect(decryptWithPassword(tampered, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a flipped salt bit is rejected", async () => {
+        const tampered = withField(vault, "salt", flipByte(vault.salt, 0));
+
+        await expect(decryptWithPassword(tampered, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a truncated ciphertext is rejected", async () => {
+        const bytes = b64decode(vault.ciphertext);
+        const tampered = withField(
+            vault,
+            "ciphertext",
+            sodium.to_base64(bytes.slice(0, bytes.length - 4)),
+        );
+
+        await expect(decryptWithPassword(tampered, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a ciphertext shorter than the auth tag is rejected", async () => {
+        const tampered = withField(
+            vault,
+            "ciphertext",
+            sodium.to_base64(b64decode(vault.ciphertext).slice(0, 4)),
+        );
+
+        await expect(decryptWithPassword(tampered, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a truncated nonce is rejected", async () => {
+        const tampered = withField(
+            vault,
+            "nonce",
+            sodium.to_base64(b64decode(vault.nonce).slice(0, NONCE_BYTES - 1)),
+        );
+
+        await expect(decryptWithPassword(tampered, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a ciphertext from another vault is rejected", async () => {
+        const other = await encryptWithPassword("a different secret", PASSWORD);
+        const spliced = withField(vault, "ciphertext", other.ciphertext);
+
+        await expect(decryptWithPassword(spliced, PASSWORD)).rejects.toThrow();
+    });
+
+    test("a missing field is rejected rather than decrypted", async () => {
+        for (const field of ["salt", "nonce", "ciphertext"]) {
+            const broken = { ...vault };
+            delete broken[field];
+
+            await expect(
+                decryptWithPassword(broken, PASSWORD),
+            ).rejects.toThrow();
+        }
+    });
+});

tests/wallet.test.js

@@ -1,4 +1,6 @@
-// Tests for the DEBUG build flag as it gates mnemonic generation.
+// Tests for src/shared/wallet.js: the DEBUG build flag as it gates mnemonic
+// generation (first two describes), and HD key derivation against published
+// known-answer vectors (rest of the file).
 //
 // The modules read the __BUILD_DEBUG__ global that esbuild replaces at bundle
 // time. Under jest the global is absent, which is exactly the release-build
@@ -92,3 +94,317 @@ describe("generateMnemonic in a debug build", () => {
         );
     });
 });
+
+// ---------------------------------------------------------------------------
+// Key derivation.
+//
+// Every address below is a published constant, not something this codebase
+// produced. Asserting against what the implementation happens to return today
+// would pass just as happily with the wrong coin type, the wrong path depth or
+// a non-empty seed passphrase, all of which silently send funds to addresses
+// no other wallet can recover.
+//
+// Vector sources:
+//
+//   VECTOR_PHRASE / VECTOR_ADDRESSES / VECTOR_PRIVATE_KEYS — the standard
+//   development recovery phrase and the first three accounts it yields at
+//   m/44'/60'/0'/0/n with an empty seed passphrase, as published in the
+//   Hardhat and Ganache documentation. Publicly known; never fund it.
+//
+//   ZERO_ENTROPY_PHRASE / ZERO_ENTROPY_ADDRESS — the BIP-39 all-zero-entropy
+//   phrase (Trezor's official BIP-39 vector set, first entry) and its
+//   m/44'/60'/0'/0/0 Ethereum address with an empty seed passphrase. A second,
+//   independently published phrase so the pin is not one vector deep.
+//
+//   BIP32_VECTOR_1_XPRV — the master key of BIP-32 test vector 1
+//   (seed 000102030405060708090a0b0c0d0e0f).
+//
+// The two Hardhat facts cross-check each other: VECTOR_PRIVATE_KEYS[n] is the
+// published key for VECTOR_ADDRESSES[n], so addressFromPrivateKey and the HD
+// path must meet at the same address from two different directions.
+
+const { HDNodeWallet, Mnemonic, verifyMessage } = require("ethers");
+const wallet = require("../src/shared/wallet");
+const { BIP44_ETH_PATH } = require("../src/shared/constants");
+
+const VECTOR_PHRASE =
+    "test test test test test test test test test test test junk";
+
+const VECTOR_ADDRESSES = [
+    "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
+    "0x70997970C51812dc3A010C7d01b50e0d17dc79C8",
+    "0x3C44CdDdB6a900fa2b585dd299e03d12FA4293BC",
+];
+
+const VECTOR_PRIVATE_KEYS = [
+    "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80",
+    "0x59c6995e998f97a5a0044966f0945389dc9e86dae88c7a8412f4603b6b78690d",
+    "0x5de4111afa1a4b94908f83103eb1f1706367c2e68ca870fc3fb9a804cdab365a",
+];
+
+const ZERO_ENTROPY_PHRASE =
+    "abandon abandon abandon abandon abandon abandon " +
+    "abandon abandon abandon abandon abandon about";
+const ZERO_ENTROPY_ADDRESS = "0x9858EfFD232B4033E47d90003D41EC34EcaEda94";
+
+const BIP32_VECTOR_1_XPRV =
+    "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqji" +
+    "ChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi";
+
+// The master (depth-0) extended private key for a phrase, which is what the
+// import-an-xprv flow is handed. Built with ethers rather than with the module
+// under test, so hdWalletFromXprv is not being checked against itself.
+function masterXprv(phrase, passphrase = "") {
+    return HDNodeWallet.fromSeed(
+        Mnemonic.fromPhrase(phrase, passphrase).computeSeed(),
+    ).extendedKey;
+}
+
+describe("hdWalletFromMnemonic", () => {
+    test("first address matches the published vector for m/44'/60'/0'/0/0", () => {
+        expect(wallet.hdWalletFromMnemonic(VECTOR_PHRASE).firstAddress).toBe(
+            VECTOR_ADDRESSES[0],
+        );
+    });
+
+    test("second published phrase derives its published address", () => {
+        expect(
+            wallet.hdWalletFromMnemonic(ZERO_ENTROPY_PHRASE).firstAddress,
+        ).toBe(ZERO_ENTROPY_ADDRESS);
+    });
+
+    test("returns the account-level xpub, which is watch-only", () => {
+        const { xpub } = wallet.hdWalletFromMnemonic(VECTOR_PHRASE);
+
+        expect(xpub.startsWith("xpub")).toBe(true);
+        // A neutered ethers node exposes no private key at all, so accept
+        // either absent or null rather than pinning which.
+        expect(
+            HDNodeWallet.fromExtendedKey(xpub).privateKey ?? null,
+        ).toBeNull();
+        expect(wallet.isValidXprv(xpub)).toBe(false);
+    });
+
+    test("the account path is the documented BIP-44 Ethereum path", () => {
+        expect(BIP44_ETH_PATH).toBe("m/44'/60'/0'/0");
+    });
+
+    test("rejects an invalid recovery phrase rather than deriving from it", () => {
+        expect(() => wallet.hdWalletFromMnemonic("not a phrase")).toThrow();
+    });
+});
+
+describe("deriveAddressFromXpub", () => {
+    const { xpub } = wallet.hdWalletFromMnemonic(VECTOR_PHRASE);
+
+    test.each([0, 1, 2])(
+        "child %i matches the published vector address",
+        (index) => {
+            expect(wallet.deriveAddressFromXpub(xpub, index)).toBe(
+                VECTOR_ADDRESSES[index],
+            );
+        },
+    );
+
+    test("agrees with hdWalletFromMnemonic at index 0", () => {
+        expect(wallet.deriveAddressFromXpub(xpub, 0)).toBe(
+            wallet.hdWalletFromMnemonic(VECTOR_PHRASE).firstAddress,
+        );
+    });
+
+    test("rejects garbage instead of returning an address", () => {
+        expect(() =>
+            wallet.deriveAddressFromXpub("xpub-nonsense", 0),
+        ).toThrow();
+    });
+});
+
+describe("hdWalletFromMnemonic seed passphrase handling", () => {
+    // The vectors above are only reproducible with an empty BIP-39 seed
+    // passphrase. This pins that the empty string reaching
+    // HDNodeWallet.fromPhrase is load-bearing: with any passphrase applied the
+    // published address is unreachable, and a wallet derived that way could
+    // not be restored anywhere else from the phrase alone.
+    test("a non-empty seed passphrase would yield a different address", () => {
+        const withPassphrase = HDNodeWallet.fromPhrase(
+            VECTOR_PHRASE,
+            "TREZOR",
+            BIP44_ETH_PATH,
+        ).deriveChild(0).address;
+
+        expect(withPassphrase).not.toBe(VECTOR_ADDRESSES[0]);
+    });
+});
+
+describe("hdWalletFromXprv", () => {
+    // hdWalletFromMnemonic derives the absolute path "m/44'/60'/0'/0" while
+    // hdWalletFromXprv derives the relative path "44'/60'/0'/0". For a
+    // depth-0 master key the two are the same derivation; these tests pin that
+    // equivalence to a published address rather than assuming it.
+    test("master xprv for the vector phrase yields the vector address", () => {
+        expect(
+            wallet.hdWalletFromXprv(masterXprv(VECTOR_PHRASE)).firstAddress,
+        ).toBe(VECTOR_ADDRESSES[0]);
+    });
+
+    test("agrees with hdWalletFromMnemonic on xpub and address", () => {
+        const fromPhrase = wallet.hdWalletFromMnemonic(VECTOR_PHRASE);
+        const fromXprv = wallet.hdWalletFromXprv(masterXprv(VECTOR_PHRASE));
+
+        expect(fromXprv).toEqual(fromPhrase);
+    });
+
+    test("derived xpub generates the same child addresses", () => {
+        const { xpub } = wallet.hdWalletFromXprv(masterXprv(VECTOR_PHRASE));
+
+        expect(
+            [0, 1, 2].map((i) => wallet.deriveAddressFromXpub(xpub, i)),
+        ).toEqual(VECTOR_ADDRESSES);
+    });
+
+    test("accepts the BIP-32 test vector 1 master key", () => {
+        const { xpub, firstAddress } =
+            wallet.hdWalletFromXprv(BIP32_VECTOR_1_XPRV);
+
+        expect(xpub.startsWith("xpub")).toBe(true);
+        expect(firstAddress).toMatch(/^0x[0-9a-fA-F]{40}$/);
+    });
+
+    test("rejects a watch-only xpub", () => {
+        const { xpub } = wallet.hdWalletFromMnemonic(VECTOR_PHRASE);
+
+        expect(() => wallet.hdWalletFromXprv(xpub)).toThrow();
+    });
+
+    test("rejects garbage", () => {
+        expect(() => wallet.hdWalletFromXprv("nonsense")).toThrow();
+    });
+});
+
+describe("isValidXprv", () => {
+    test.each([
+        ["BIP-32 test vector 1 master key", BIP32_VECTOR_1_XPRV, true],
+        ["the empty string", "", false],
+        ["garbage", "not-a-key", false],
+        ["a bare private key", VECTOR_PRIVATE_KEYS[0], false],
+        ["a truncated xprv", BIP32_VECTOR_1_XPRV.slice(0, -6), false],
+        ["an xprv with an extra character", BIP32_VECTOR_1_XPRV + "a", false],
+    ])("%s -> %s", (_name, key, expected) => {
+        expect(wallet.isValidXprv(key)).toBe(expected);
+    });
+
+    test("a watch-only xpub is not an xprv", () => {
+        const { xpub } = wallet.hdWalletFromMnemonic(VECTOR_PHRASE);
+
+        expect(wallet.isValidXprv(xpub)).toBe(false);
+    });
+
+    // Skipped: this asserts the correct behaviour, which the code does not
+    // currently have. isValidXprv gates the paste-your-extended-private-key
+    // import in src/popup/views/addWallet.js:215, and it accepts a key with a
+    // one-character typo: ethers' HDNodeWallet.fromExtendedKey skips base58
+    // checksum verification whenever the decoded payload is the usual 82
+    // bytes, which is the whole point of that checksum. Measured on this
+    // vector: changing any one of the last 14 characters passes validation,
+    // and for 9 of those 14 positions the import silently yields a *different*
+    // wallet (e.g. 0x3F334f0a356d6B46B1d70B590E7437D77100d28D instead of
+    // 0x022b971dFF0C43305e691DEd7a14367AF19D6407) with no error shown.
+    // Tracked as https://git.eeqj.de/sneak/AutistMask/issues/210; out of scope
+    // here, which is tests only. Unskip when it is fixed.
+    test.skip("rejects an extended key with a one-character typo", () => {
+        const index = BIP32_VECTOR_1_XPRV.length - 8;
+        const typo =
+            BIP32_VECTOR_1_XPRV.slice(0, index) +
+            (BIP32_VECTOR_1_XPRV[index] === "a" ? "b" : "a") +
+            BIP32_VECTOR_1_XPRV.slice(index + 1);
+
+        expect(wallet.isValidXprv(typo)).toBe(false);
+    });
+});
+
+describe("isValidMnemonic", () => {
+    test.each([
+        ["the vector phrase", VECTOR_PHRASE, true],
+        ["the BIP-39 zero-entropy phrase", ZERO_ENTROPY_PHRASE, true],
+        [
+            "a 12-word phrase with a bad checksum",
+            "abandon abandon abandon abandon abandon abandon " +
+                "abandon abandon abandon abandon abandon abandon",
+            false,
+        ],
+        ["an 11-word phrase", "abandon ".repeat(10) + "about", false],
+        ["a word outside the wordlist", VECTOR_PHRASE + " zzzzzz", false],
+        ["the empty string", "", false],
+        ["garbage", "correct horse battery staple", false],
+    ])("%s -> %s", (_name, phrase, expected) => {
+        expect(wallet.isValidMnemonic(phrase)).toBe(expected);
+    });
+});
+
+describe("addressFromPrivateKey", () => {
+    test.each([0, 1, 2])(
+        "published key %i yields its published address",
+        (index) => {
+            expect(
+                wallet.addressFromPrivateKey(VECTOR_PRIVATE_KEYS[index]),
+            ).toBe(VECTOR_ADDRESSES[index]);
+        },
+    );
+
+    test("rejects a key of the wrong length", () => {
+        expect(() => wallet.addressFromPrivateKey("0xdeadbeef")).toThrow();
+    });
+
+    test("rejects the empty string", () => {
+        expect(() => wallet.addressFromPrivateKey("")).toThrow();
+    });
+});
+
+describe("getSignerForAddress", () => {
+    test.each([0, 1, 2])("hd wallet, address index %i", (index) => {
+        const signer = wallet.getSignerForAddress(
+            { type: "hd" },
+            index,
+            VECTOR_PHRASE,
+        );
+
+        expect(signer.address).toBe(VECTOR_ADDRESSES[index]);
+        expect(signer.privateKey).toBe(VECTOR_PRIVATE_KEYS[index]);
+    });
+
+    test.each([0, 1, 2])("xprv wallet, address index %i", (index) => {
+        const signer = wallet.getSignerForAddress(
+            { type: "xprv" },
+            index,
+            masterXprv(VECTOR_PHRASE),
+        );
+
+        expect(signer.address).toBe(VECTOR_ADDRESSES[index]);
+        expect(signer.privateKey).toBe(VECTOR_PRIVATE_KEYS[index]);
+    });
+
+    test("single private key ignores the address index", () => {
+        for (const index of [0, 1, 2]) {
+            const signer = wallet.getSignerForAddress(
+                { type: "privkey" },
+                index,
+                VECTOR_PRIVATE_KEYS[1],
+            );
+
+            expect(signer.address).toBe(VECTOR_ADDRESSES[1]);
+        }
+    });
+
+    test("the returned signer signs recoverably as the expected address", async () => {
+        const signer = wallet.getSignerForAddress(
+            { type: "hd" },
+            1,
+            VECTOR_PHRASE,
+        );
+        const message = "AutistMask derivation test";
+
+        const signature = await signer.signMessage(message);
+
+        expect(verifyMessage(message, signature)).toBe(VECTOR_ADDRESSES[1]);
+    });
+});