fix(lite): lock/unlock parity — shared attempt-lockout, immediate unlock state, no dead PIN, surfaced encrypt failure

Lite-parity audit, FIX C (gating/validation/presentation only — no encrypt/unlock/send backend call changed):
- Lite unlock went straight to the backend with no lockout. New App::unlockLiteWallet() runs the SAME
  escalating, persisted attempt-lockout as the full node (restoreLockoutState/applyUnlockFailure), wired into
  the Settings unlock, the send-time prompt and the lock screen. A wrong-passphrase failure counts; an
  already-unlocked/not-encrypted result does not.
- state_.locked is now cleared immediately on a successful unlock (the ~2s status poll lagged, so the UI
  stayed "locked" after a correct passphrase).
- PIN quick-unlock controls are hidden in lite Settings — lite has no PIN vault, so they were dead.
- A create/restore whose passphrase encryption FAILS now raises a one-shot visible error
  (takeEncryptionFailureNotice -> lite_encrypt_failed_unencrypted) instead of only a log line; the wallet is
  left open but unencrypted. Fixed the flag on BOTH the lifecycle and the direct create/restore encrypt paths.
- A background sync save is skipped while an encrypted wallet is unlocked (the backend save re-locks it),
  resuming once locked.

Compile- and unit-verified (testLiteWalletControllerLockUnlockParity covers the save-deferral + encrypt-failure
notice, run twice for the flaky guard); the lock-screen lockout/PIN-hiding UX itself is runtime/GUI-only and
not exercised here — worth a manual lite GUI pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app.cpp

@@ -965,6 +965,9 @@ void App::update()
         lite_wallet_->pumpAsyncOpen();
         // Likewise finalize any completed async lifecycle request (Settings-page create/open/restore).
         lite_wallet_->pumpLifecycleResult();
+        // A create/restore whose passphrase encryption failed left the wallet UNENCRYPTED (previously log-only): say so.
+        if (lite_wallet_->takeEncryptionFailureNotice())
+            ui::Notifications::instance().error(TR("lite_encrypt_failed_unencrypted"), 15.0f);
         // Deliver finished wallet ops (new address / import / encrypt / decrypt) to their UI callbacks.
         lite_wallet_->pumpWalletOps();
         // A server switch deferred behind an in-flight wallet op: retry it. This may replace lite_wallet_; the rest of
@@ -3829,12 +3832,13 @@ void App::renderLiteUnlockPrompt()
         const float btnW = 130.0f * dp;
         bool doUnlock = ui::material::TactileButton(TR("lite_unlock_btn"), ImVec2(btnW, 0)) || entered;
         if (doUnlock) {
-            const bool ok = lite_wallet_->unlockWallet(pass);
+            std::string unlockErr;
+            const bool ok = unlockLiteWallet(std::string(pass), &unlockErr);
             sodium_memzero(pass, sizeof(pass));
             if (ok) ui::Notifications::instance().success(TR("lite_unlock_ok"), 5.0f);
             else {
-                wallet::liteLog(std::string("Unlock failed: ") + TR("lite_unlock_failed"));
-                ui::Notifications::instance().error(TR("lite_unlock_failed"));
+                wallet::liteLog(std::string("Unlock failed: ") + unlockErr);
+                ui::Notifications::instance().error(unlockErr);
             }
             lite_unlock_prompt_ = false;
             ImGui::CloseCurrentPopup();

src/app.h

@@ -333,6 +333,10 @@ public:
     // Lock the lite wallet AND immediately tear down the chat session (the lite backend `lock`
     // doesn't update state_.locked until the next poll, so chat secrets would otherwise linger).
     bool lockLiteWallet();
+    // Unlock the lite wallet with the same escalating attempt-lockout as the full node (persisted across restarts)
+    // and set state_.locked=false right away on success (the poll lags). Takes the passphrase by value and wipes
+    // it. On failure *err (if given) holds a user-facing reason ("Unlock failed..." or the lockout wait).
+    bool unlockLiteWallet(std::string passphrase, std::string* err = nullptr);
     // (Re)build the lite controller from current settings so a changed lite-server selection
     // takes effect. No-op on non-lite/unlinked builds; preserves a live wallet (see app.cpp).
     void rebuildLiteWallet(bool force = false);

src/app_network.cpp

@@ -5427,6 +5427,69 @@ bool App::lockLiteWallet()
     return ok;
 }
 
+bool App::unlockLiteWallet(std::string passphrase, std::string* err)
+{
+    const auto fail = [&](const std::string& m) { if (err) *err = m; };
+    const auto waitMsg = [](long long secs) {
+        char msg[128];
+        snprintf(msg, sizeof(msg), TR("sec_too_many_attempts_wait"), (double)secs);
+        return std::string(msg);
+    };
+    if (!lite_wallet_ || !lite_wallet_->walletOpen() || passphrase.empty()) {
+        wallet::secureWipeLiteSecret(passphrase);
+        fail(TR("lite_unlock_failed"));
+        return false;   // nothing to attempt: not a wrong-credential failure, not counted
+    }
+    // Restore the persisted attempt count once per session (the full-node lock screen does the same).
+    if (!lock_state_restored_) {
+        lock_state_restored_ = true;
+        restoreLockoutState();
+    }
+    // Enforce the lockout from the persisted wall-clock expiry: lite has no per-frame lockout timer.
+    if (settings_ && settings_->getLockStateWallet() == settings_->getActiveWalletFile()) {
+        const long long remaining = settings_->getLockoutUntilEpoch() - (long long)std::time(nullptr);
+        if (remaining > 0) {
+            wallet::secureWipeLiteSecret(passphrase);
+            fail(waitMsg(remaining));
+            return false;
+        }
+    }
+    lock_lockout_timer_ = 0.0f;   // expired: don't let a stale in-memory value re-arm the curve
+
+    const bool ok = lite_wallet_->unlockWallet(std::move(passphrase));   // wipes the passphrase
+    if (!ok) {
+        const auto st = lite_wallet_->encryptionStatus();
+        if (st.ok && !(st.encrypted && st.locked)) {
+            // Not a wrong credential: already unlocked (e.g. a racing prompt) or not encrypted. Don't count it.
+            state_.encrypted = st.encrypted;
+            state_.locked = false;
+            if (st.encrypted) { idle_.noteActivity(); return true; }
+            fail(TR("lite_unlock_failed"));
+            return false;
+        }
+        applyUnlockFailure(TR("lite_unlock_failed"));   // bump counter, arm lockout curve, persist
+        fail(lock_lockout_timer_ > 0.0f ? waitMsg((long long)std::ceil(lock_lockout_timer_))
+                                        : std::string(TR("lite_unlock_failed")));
+        return false;
+    }
+
+    // Success: clear the attempt state (and its persisted copy) and reflect the unlock NOW — the next poll lags.
+    lock_unlock_in_progress_ = false;
+    lock_error_msg_.clear();
+    lock_attempts_ = 0;
+    lock_lockout_timer_ = 0.0f;
+    if (settings_ && settings_->getLockFailedAttempts() != 0) {
+        settings_->setLockFailedAttempts(0);
+        settings_->setLockoutUntilEpoch(0);
+        settings_->save();
+    }
+    memset(lock_passphrase_buf_, 0, sizeof(lock_passphrase_buf_));
+    idle_.noteActivity();
+    state_.encrypted = true;
+    state_.locked = false;
+    return true;
+}
+
 bool App::seedChatDemoData()
 {
     if (!chat::hushChatFeatureEnabledAtBuild()) return false;

src/app_security.cpp

@@ -548,6 +548,15 @@ void App::applyUnlockNotCounted(const std::string& msg) {
 }
 
 void App::unlockWallet(const std::string& passphrase, int timeout) {
+    if (lite_wallet_) {   // lite: backend unlock with the shared attempt-lockout (no RPC/daemon)
+        std::string liteErr;
+        if (!unlockLiteWallet(passphrase, &liteErr)) {
+            lock_error_msg_ = liteErr;
+            lock_error_timer_ = 3.0f;
+            lock_timer_armed_at_ = std::chrono::steady_clock::now();
+        }
+        return;
+    }
     if (!rpc_ || !rpc_->isConnected() || !worker_) return;
     lock_unlock_in_progress_ = true;
 

src/ui/pages/settings_page.cpp

@@ -1708,7 +1708,11 @@ void RenderSettingsPage(App* app) {
 
                     // PIN unlock controls, trailing the auto-lock combo on the same row.
                     bool isEncryptedPIN = app->state().isEncrypted();
-                    if (isEncryptedPIN) {
+                    // Lite has no PIN quick-unlock: its unlock paths (Settings, send-time prompt) take the passphrase
+                    // directly and never consult a PIN vault, so these controls would be dead. Hide them.
+                    if (app->isLiteBuild()) {
+                        // nothing to show
+                    } else if (isEncryptedPIN) {
                         bool hasPIN = app->hasPinVault();
                         float pinBtnW = std::min(rowBtnW({TR("settings_set_pin"), TR("settings_change_pin"), TR("settings_remove_pin")}), (secColW - Layout::spacingSm()) * 0.5f);
 
@@ -2172,9 +2176,10 @@ void RenderSettingsPage(App* app) {
                                 if (ImGui::IsItemHovered()) material::Tooltip("%s", TR("tt_lite_unlock_pass"));
                                 ImGui::SetCursorScreenPos(ImVec2(leftX, ImGui::GetCursorScreenPos().y));
                                 if (TactileButton(TrId("lite_unlock", "LiteUnlock").c_str(), ImVec2(0, 0), S.resolveFont("button"))) {
-                                    const bool ok = app->liteWallet()->unlockWallet(s_settingsState.lite_enc_pass);
+                                    std::string unlockErr;
+                                    const bool ok = app->unlockLiteWallet(std::string(s_settingsState.lite_enc_pass), &unlockErr);
                                     sodium_memzero(s_settingsState.lite_enc_pass, sizeof(s_settingsState.lite_enc_pass));
-                                    s_settingsState.lite_encryption_status = ok ? TR("lite_wallet_unlocked") : TR("lite_unlock_failed");
+                                    s_settingsState.lite_encryption_status = ok ? std::string(TR("lite_wallet_unlocked")) : unlockErr;
                                 }
                                 if (ImGui::IsItemHovered()) material::Tooltip("%s", TR("tt_lite_unlock"));
                             } else {

src/util/i18n.cpp

@@ -1354,6 +1354,7 @@ void I18n::loadBuiltinEnglish()
         strings_["lite_unlock_btn"] = "Unlock";
         strings_["lite_unlock_ok"] = "Wallet unlocked — you can send now";
         strings_["lite_unlock_failed"] = "Unlock failed — wrong passphrase?";
+        strings_["lite_encrypt_failed_unencrypted"] = "Wallet encryption failed — your wallet may still be UNENCRYPTED. Open Settings > Security and set the passphrase again.";
 
         // Send Tab
         strings_["pay_from"] = "Pay From";

src/wallet/lite_wallet_controller.cpp

@@ -110,6 +110,21 @@ bool persistAfterBroadcast(LiteClientBridge& bridge)
     return false;
 }
 
+// True when the wallet is encrypted AND currently unlocked. The backend's `save` re-locks such a wallet (do_save),
+// so a background save must not run under a user who just unlocked. Fail-open: any error reads as "not unlocked" and
+// the save proceeds as it always did.
+bool liteWalletEncryptedAndUnlocked(LiteClientBridge& bridge)
+{
+    const auto r = bridge.execute("encryptionstatus", "");
+    if (!r.ok) return false;
+    try {
+        const auto j = nlohmann::json::parse(r.value);
+        return j.is_object() && !j.contains("error") && j.value("encrypted", false) && !j.value("locked", false);
+    } catch (...) {
+        return false;
+    }
+}
+
 // The detached sync/rescan thread. `firstCommand` is "sync" or "rescan"; every retry is "sync" (a failed rescan has
 // already cleared the wallet, so re-running it would throw away the partial progress). Partial progress is saved after
 // every attempt. Captures shared state only.
@@ -129,7 +144,12 @@ void runLiteScanThread(const std::shared_ptr<LiteClientBridge>& bridge,
                 op.error = call.error.empty() ? "sync failed" : call.error;
             }
             // The backend does NOT auto-save after a sync; persist what was scanned even when the attempt failed.
-            if (!bridge->execute("save", "").ok)   // W5-2
+            // Not while the user has the wallet unlocked: the backend save re-locks an encrypted+unlocked wallet, which
+            // would yank the unlock out from under a spend/unlock in progress. The progress is saved by the next scan
+            // once locked (and by the shutdown save); a crash in between only costs a re-scan from the checkpoint.
+            if (liteWalletEncryptedAndUnlocked(*bridge))
+                liteLog("sync save deferred: wallet is unlocked (a save would re-lock it)");
+            else if (!bridge->execute("save", "").ok)   // W5-2
                 liteLog("save failed after sync — the next launch will re-scan from the checkpoint");
             if (op.ok) {
                 scan->setError(std::string());
@@ -938,9 +958,11 @@ void LiteWalletController::applyPendingLifecycleSecurity()
     if (op == PendingSecurityOp::Encrypt) {
         // encryptWallet() takes its own copy and wipes it; the backend encrypts + locks + saves.
         const auto enc = encryptWallet(pendingLifecyclePassphrase_);
-        if (!enc.ok)
+        if (!enc.ok) {
+            lifecycleEncryptFailed_ = true;   // surfaced to the user by the App (takeEncryptionFailureNotice)
             liteLog("wallet created/restored but ENCRYPTION FAILED — wallet is NOT encrypted: " +
                     enc.error);
+        }
     } else if (op == PendingSecurityOp::Unlock) {
         if (!unlockWallet(pendingLifecyclePassphrase_))
             liteLog("wallet opened but unlock failed (wrong passphrase?)");
@@ -1597,6 +1619,13 @@ bool LiteWalletController::unlockWallet(std::string passphrase)
     return ok;
 }
 
+bool LiteWalletController::takeEncryptionFailureNotice()
+{
+    const bool failed = lifecycleEncryptFailed_;
+    lifecycleEncryptFailed_ = false;
+    return failed;
+}
+
 bool LiteWalletController::lockWallet()
 {
     if (!walletOpen_.load() || !bridge_) return false;
@@ -1767,7 +1796,10 @@ LiteWalletLifecycleResult LiteWalletController::createWallet(LiteWalletCreateReq
     // copy and wipes it.
     if (walletOpen_.load() && !request.passphrase.empty()) {
         const auto enc = encryptWallet(request.passphrase);
-        if (!enc.ok) liteLog("wallet created but encryption failed: " + enc.error);
+        if (!enc.ok) {
+            lifecycleEncryptFailed_ = true;   // the wallet is open but NOT encrypted; App surfaces this
+            liteLog("wallet created but encryption failed: " + enc.error);
+        }
     }
     secureWipeLiteSecret(request.passphrase);
     return result;
@@ -1797,7 +1829,10 @@ LiteWalletLifecycleResult LiteWalletController::restoreWallet(LiteWalletRestoreR
     // If the user supplied a passphrase, encrypt the restored wallet with it now that it's open (W5-3).
     if (walletOpen_.load() && !request.passphrase.empty()) {
         const auto enc = encryptWallet(request.passphrase);
-        if (!enc.ok) liteLog("wallet restored but encryption failed: " + enc.error);
+        if (!enc.ok) {
+            lifecycleEncryptFailed_ = true;   // the wallet is open but NOT encrypted; App surfaces this
+            liteLog("wallet restored but encryption failed: " + enc.error);
+        }
     }
     secureWipeLiteSecret(request.seedPhrase);
     secureWipeLiteSecret(request.passphrase);

src/wallet/lite_wallet_controller.h

@@ -363,6 +363,9 @@ public:
     bool lockWallet();
     LiteEncryptionResult decryptWallet(std::string passphrase);
     LiteEncryptionStatus encryptionStatus();
+    // True once (then cleared) if the passphrase encryption of a just-created/restored wallet FAILED, leaving it
+    // unencrypted. Main thread; the App turns it into a visible error instead of a log line.
+    bool takeEncryptionFailureNotice();
 
     // Poll sync status + fetch balance/addresses/transactions, and apply the result into the
     // app's WalletState. Returns true if state was updated. Safe no-op when no wallet is open.
@@ -488,6 +491,7 @@ private:
     enum class PendingSecurityOp { None, Encrypt, Unlock };
     std::string pendingLifecyclePassphrase_;                       // main-thread only; wiped after use
     PendingSecurityOp pendingLifecycleSecurityOp_ = PendingSecurityOp::None;
+    bool lifecycleEncryptFailed_ = false;                          // main-thread only; see takeEncryptionFailureNotice()
     void stashPendingLifecycleSecurity(const std::string& passphrase, PendingSecurityOp op);
     void applyPendingLifecycleSecurity();  // encrypt (create/restore) or unlock (open), then wipe
     void clearPendingLifecycleSecurity();  // wipe + reset (rejected request / failed open)