feat: Add menu option to show recovery phrase for existing wallets

Add "Show Recovery Phrase" menu item under Settings that allows users
to view their mnemonic seed phrase for existing HD wallets with a
streamlined view-only interface.

Menu Integration:
- Added Settings → Show Recovery Phrase menu option
- Menu item positioned between "Change Passphrase" and "Unlock Wallet"
- Enabled for HD wallets with private keys
- Disabled for watch-only wallets (NoKeys status)

View-Only Dialog Mode:
- New optional viewOnly parameter in MnemonicVerificationDialog constructor
- Simplified interface without verification step for viewing existing mnemonics
- Window title: "Your Recovery Phrase" (vs "Save Your Mnemonic" for new wallets)
- Button: Single "Close" button (Cancel button hidden)
- Checkbox: "I have written down" checkbox hidden
- Flow: Single-step view without word verification requirement
- Adjusted warning text appropriate for viewing existing phrase

Security Features:
- Prompts for passphrase if wallet is encrypted (unlocks temporarily)
- Validates wallet capabilities (HD enabled, has private keys)
- Clears mnemonic from memory immediately after dialog creation
- Properly restores wallet lock state after viewing:
  * Returns to locked state if was locked
  * Returns to unlocked-for-mixing state if was in that mode
- Secure memory handling throughout with SecureString

Error Handling:
- Clear error messages for non-HD wallets
- Clear error messages for watch-only wallets
- Graceful handling of user cancellation during unlock
- Proper error recovery with lock state restoration

Backward Compatibility:
- viewOnly parameter defaults to false
- Original verification flow unchanged for new wallet creation
- Existing MnemonicVerificationDialog behavior preserved

This allows users to backup their recovery phrase after wallet creation
without needing to recreate the wallet, with a cleaner UX that skips
unnecessary verification steps when viewing an existing mnemonic.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: 2 people

src/qt/bitcoingui.cpp

@@ -394,6 +394,8 @@ void BitcoinGUI::createActions()
     backupWalletAction->setStatusTip(tr("Backup wallet to another location"));
     changePassphraseAction = new QAction(tr("&Change Passphrase…"), this);
     changePassphraseAction->setStatusTip(tr("Change the passphrase used for wallet encryption"));
+    showMnemonicAction = new QAction(tr("&Show Recovery Phrase…"), this);
+    showMnemonicAction->setStatusTip(tr("Show the recovery phrase (mnemonic seed) for this wallet"));
     unlockWalletAction = new QAction(tr("&Unlock Wallet…"), this);
     unlockWalletAction->setToolTip(tr("Unlock wallet"));
     lockWalletAction = new QAction(tr("&Lock Wallet"), this);
@@ -502,6 +504,7 @@ void BitcoinGUI::createActions()
         connect(encryptWalletAction, &QAction::triggered, walletFrame, &WalletFrame::encryptWallet);
         connect(backupWalletAction, &QAction::triggered, walletFrame, &WalletFrame::backupWallet);
         connect(changePassphraseAction, &QAction::triggered, walletFrame, &WalletFrame::changePassphrase);
+        connect(showMnemonicAction, &QAction::triggered, walletFrame, &WalletFrame::showMnemonic);
         connect(unlockWalletAction, &QAction::triggered, walletFrame, &WalletFrame::unlockWallet);
         connect(lockWalletAction, &QAction::triggered, walletFrame, &WalletFrame::lockWallet);
         connect(signMessageAction, &QAction::triggered, [this]{ showNormalIfMinimized(); });
@@ -620,6 +623,7 @@ void BitcoinGUI::createMenuBar()
     {
         settings->addAction(encryptWalletAction);
         settings->addAction(changePassphraseAction);
+        settings->addAction(showMnemonicAction);
         settings->addAction(unlockWalletAction);
         settings->addAction(lockWalletAction);
         settings->addSeparator();
@@ -1040,6 +1044,7 @@ void BitcoinGUI::setWalletActionsEnabled(bool enabled)
     encryptWalletAction->setEnabled(enabled);
     backupWalletAction->setEnabled(enabled);
     changePassphraseAction->setEnabled(enabled);
+    showMnemonicAction->setEnabled(enabled);
     unlockWalletAction->setEnabled(enabled);
     lockWalletAction->setEnabled(enabled);
     signMessageAction->setEnabled(enabled);
@@ -1936,6 +1941,7 @@ void BitcoinGUI::setEncryptionStatus(int status)
         encryptWalletAction->setChecked(false);
         changePassphraseAction->setEnabled(false);
         encryptWalletAction->setEnabled(false);
+        showMnemonicAction->setEnabled(false);
         break;
     case WalletModel::Unencrypted:
         labelWalletEncryptionIcon->show();

src/qt/bitcoingui.h

@@ -157,6 +157,7 @@ class BitcoinGUI : public QMainWindow
     QAction* encryptWalletAction = nullptr;
     QAction* backupWalletAction = nullptr;
     QAction* changePassphraseAction = nullptr;
+    QAction* showMnemonicAction = nullptr;
     QAction* unlockWalletAction = nullptr;
     QAction* lockWalletAction = nullptr;
     QAction* aboutQtAction = nullptr;

src/qt/mnemonicverificationdialog.cpp

@@ -23,11 +23,12 @@
 
 #include <algorithm>
 
-MnemonicVerificationDialog::MnemonicVerificationDialog(const SecureString& mnemonic, QWidget *parent) :
+MnemonicVerificationDialog::MnemonicVerificationDialog(const SecureString& mnemonic, QWidget *parent, bool viewOnly) :
     QDialog(parent, GUIUtil::dialog_flags),
     ui(new Ui::MnemonicVerificationDialog),
     m_mnemonic(mnemonic),
-    m_mnemonic_revealed(false)
+    m_mnemonic_revealed(false),
+    m_view_only(viewOnly)
 {
     ui->setupUi(this);
 
@@ -39,7 +40,7 @@ MnemonicVerificationDialog::MnemonicVerificationDialog(const SecureString& mnemo
     setMinimumSize(QSize(550, 360));
     resize(minimumSize());
 
-    setWindowTitle(tr("Save Your Mnemonic"));
+    setWindowTitle(m_view_only ? tr("Your Recovery Phrase") : tr("Save Your Mnemonic"));
 
     // Words will be parsed on-demand to minimize exposure time in non-secure memory
     // m_words is intentionally left empty initially
@@ -79,16 +80,19 @@ MnemonicVerificationDialog::MnemonicVerificationDialog(const SecureString& mnemo
     // Connections
     connect(ui->showMnemonicButton, &QPushButton::clicked, this, &MnemonicVerificationDialog::onShowMnemonicClicked);
     connect(ui->hideMnemonicButton,  &QPushButton::clicked, this, &MnemonicVerificationDialog::onHideMnemonicClicked);
-    connect(ui->writtenDownCheckbox, &QCheckBox::toggled, this, [this](bool checked) {
-        if (checked && m_has_ever_revealed) setupStep2();
-    });
-    connect(ui->word1Edit, &QLineEdit::textChanged, this, &MnemonicVerificationDialog::onWord1Changed);
-    connect(ui->word2Edit, &QLineEdit::textChanged, this, &MnemonicVerificationDialog::onWord2Changed);
-    connect(ui->word3Edit, &QLineEdit::textChanged, this, &MnemonicVerificationDialog::onWord3Changed);
-    connect(ui->showMnemonicAgainButton, &QPushButton::clicked, this, &MnemonicVerificationDialog::onShowMnemonicAgainClicked);
+
+    if (!m_view_only) {
+        connect(ui->writtenDownCheckbox, &QCheckBox::toggled, this, [this](bool checked) {
+            if (checked && m_has_ever_revealed) setupStep2();
+        });
+        connect(ui->word1Edit, &QLineEdit::textChanged, this, &MnemonicVerificationDialog::onWord1Changed);
+        connect(ui->word2Edit, &QLineEdit::textChanged, this, &MnemonicVerificationDialog::onWord2Changed);
+        connect(ui->word3Edit, &QLineEdit::textChanged, this, &MnemonicVerificationDialog::onWord3Changed);
+        connect(ui->showMnemonicAgainButton, &QPushButton::clicked, this, &MnemonicVerificationDialog::onShowMnemonicAgainClicked);
+    }
 
     // Button box
-    ui->buttonBox->button(QDialogButtonBox::Ok)->setText(tr("Continue"));
+    ui->buttonBox->button(QDialogButtonBox::Ok)->setText(m_view_only ? tr("Close") : tr("Continue"));
     connect(ui->buttonBox, &QDialogButtonBox::accepted, this, &MnemonicVerificationDialog::accept);
     connect(ui->buttonBox, &QDialogButtonBox::rejected, this, &MnemonicVerificationDialog::reject);
 
@@ -111,7 +115,20 @@ void MnemonicVerificationDialog::setupStep1()
     ui->writtenDownCheckbox->setEnabled(false);
     ui->writtenDownCheckbox->setChecked(false);
     m_mnemonic_revealed = false;
-    ui->buttonBox->hide();
+
+    // In view-only mode, hide the checkbox and show buttonBox immediately
+    if (m_view_only) {
+        ui->writtenDownCheckbox->hide();
+        ui->buttonBox->show();
+        // Hide Cancel button in view-only mode - only Close button is needed
+        if (QAbstractButton* cancelBtn = ui->buttonBox->button(QDialogButtonBox::Cancel)) {
+            cancelBtn->hide();
+        }
+    } else {
+        ui->writtenDownCheckbox->show();
+        ui->buttonBox->hide();
+    }
+
     // Restore original minimum size (in case we came back from Step 2)
     setMinimumSize(QSize(550, 360));
 
@@ -125,12 +142,19 @@ void MnemonicVerificationDialog::setupStep1()
 
     // Set warning and instruction text with themed colors
     // Font sizes and weights are defined in general.css
-    ui->warningLabel->setText(
-        tr("WARNING: If you lose your mnemonic seed phrase, you will lose access to your wallet forever. Write it down in a safe place and never share it with anyone."));
-    ui->warningLabel->setStyleSheet(GUIUtil::getThemedStyleQString(GUIUtil::ThemedStyle::TS_ERROR));
-
-    ui->instructionLabel->setText(
-        tr("Please write down these words in order. You will need them to restore your wallet."));
+    if (m_view_only) {
+        ui->warningLabel->setText(
+            tr("WARNING: Never share your recovery phrase with anyone. Store it securely offline."));
+        ui->warningLabel->setStyleSheet(GUIUtil::getThemedStyleQString(GUIUtil::ThemedStyle::TS_ERROR));
+        ui->instructionLabel->setText(
+            tr("These words can restore your wallet. Keep them safe and private."));
+    } else {
+        ui->warningLabel->setText(
+            tr("WARNING: If you lose your mnemonic seed phrase, you will lose access to your wallet forever. Write it down in a safe place and never share it with anyone."));
+        ui->warningLabel->setStyleSheet(GUIUtil::getThemedStyleQString(GUIUtil::ThemedStyle::TS_ERROR));
+        ui->instructionLabel->setText(
+            tr("Please write down these words in order. You will need them to restore your wallet."));
+    }
 
     // Reduce extra padding to avoid an over-padded look
     if (auto outer = findChild<QVBoxLayout*>("verticalLayout_step1")) {
@@ -250,7 +274,9 @@ void MnemonicVerificationDialog::onShowMnemonicClicked()
     buildMnemonicGrid(true);
     ui->showMnemonicButton->hide();
     ui->hideMnemonicButton->show();
-    ui->writtenDownCheckbox->setEnabled(true);
+    if (!m_view_only) {
+        ui->writtenDownCheckbox->setEnabled(true);
+    }
     m_mnemonic_revealed = true;
     m_has_ever_revealed = true;
 }
@@ -320,11 +346,14 @@ void MnemonicVerificationDialog::updateWordValidation()
 
 void MnemonicVerificationDialog::accept()
 {
-    if (!validateWord(ui->word1Edit->text().trimmed().toLower(), m_selected_positions[0]) ||
-        !validateWord(ui->word2Edit->text().trimmed().toLower(), m_selected_positions[1]) ||
-        !validateWord(ui->word3Edit->text().trimmed().toLower(), m_selected_positions[2])) {
-        QMessageBox::warning(this, tr("Verification Failed"), tr("One or more words are incorrect. Please try again."));
-        return;
+    // In view-only mode, skip verification
+    if (!m_view_only) {
+        if (!validateWord(ui->word1Edit->text().trimmed().toLower(), m_selected_positions[0]) ||
+            !validateWord(ui->word2Edit->text().trimmed().toLower(), m_selected_positions[1]) ||
+            !validateWord(ui->word3Edit->text().trimmed().toLower(), m_selected_positions[2])) {
+            QMessageBox::warning(this, tr("Verification Failed"), tr("One or more words are incorrect. Please try again."));
+            return;
+        }
     }
     QDialog::accept();
 }

src/qt/mnemonicverificationdialog.h

@@ -20,7 +20,7 @@ class MnemonicVerificationDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit MnemonicVerificationDialog(const SecureString& mnemonic, QWidget *parent = nullptr);
+    explicit MnemonicVerificationDialog(const SecureString& mnemonic, QWidget *parent = nullptr, bool viewOnly = false);
     ~MnemonicVerificationDialog();
 
     void accept() override;
@@ -51,6 +51,7 @@ private Q_SLOTS:
     QList<int> m_selected_positions;
     bool m_mnemonic_revealed;
     bool m_has_ever_revealed{false};
+    bool m_view_only{false};
     class QGridLayout* m_gridLayout{nullptr};
     QSize m_defaultSize;
 };

src/qt/walletframe.cpp

@@ -310,6 +310,13 @@ void WalletFrame::changePassphrase()
         walletView->changePassphrase();
 }
 
+void WalletFrame::showMnemonic()
+{
+    WalletView *walletView = currentWalletView();
+    if (walletView)
+        walletView->showMnemonic();
+}
+
 void WalletFrame::unlockWallet()
 {
     WalletView *walletView = currentWalletView();

src/qt/walletframe.h

@@ -100,6 +100,8 @@ public Q_SLOTS:
     void backupWallet();
     /** Change encrypted wallet passphrase */
     void changePassphrase();
+    /** Show wallet mnemonic/recovery phrase */
+    void showMnemonic();
     /** Ask for passphrase to unlock wallet temporarily */
     void unlockWallet();
     /** Lock wallet */

src/qt/walletview.cpp

@@ -11,6 +11,7 @@
 #include <qt/askpassphrasedialog.h>
 #include <qt/clientmodel.h>
 #include <qt/guiutil.h>
+#include <qt/mnemonicverificationdialog.h>
 #include <qt/optionsmodel.h>
 #include <qt/overviewpage.h>
 #include <qt/receivecoinsdialog.h>
@@ -27,6 +28,7 @@
 
 #include <QHBoxLayout>
 #include <QLabel>
+#include <QMessageBox>
 #include <QProgressDialog>
 #include <QPushButton>
 #include <QSettings>
@@ -325,6 +327,54 @@ void WalletView::changePassphrase()
     GUIUtil::ShowModalDialogAsynchronously(dlg);
 }
 
+void WalletView::showMnemonic()
+{
+    // Check if wallet supports mnemonic retrieval
+    if (walletModel->wallet().privateKeysDisabled()) {
+        QMessageBox::warning(this, tr("No Recovery Phrase"),
+            tr("This wallet does not have private keys and therefore has no recovery phrase."));
+        return;
+    }
+
+    if (!walletModel->wallet().hdEnabled()) {
+        QMessageBox::warning(this, tr("No Recovery Phrase"),
+            tr("This wallet was not created with HD (Hierarchical Deterministic) mode and does not have a recovery phrase."));
+        return;
+    }
+
+    // Request unlock if needed - UnlockContext will restore lock state on destruction
+    WalletModel::UnlockContext ctx(walletModel->requestUnlock());
+    if (!ctx.isValid()) {
+        // User cancelled unlock
+        return;
+    }
+
+    // Retrieve mnemonic
+    SecureString mnemonic;
+    SecureString mnemonic_passphrase;
+    bool has_mnemonic = walletModel->wallet().getMnemonic(mnemonic, mnemonic_passphrase);
+
+    if (!has_mnemonic || mnemonic.empty()) {
+        QMessageBox::warning(this, tr("Mnemonic Retrieval Failed"),
+            tr("Could not retrieve the recovery phrase from this wallet."));
+        return;
+    }
+
+    // Show mnemonic verification dialog in view-only mode (no verification required)
+    MnemonicVerificationDialog verify_dialog(mnemonic, this, true);
+    verify_dialog.setWindowModality(Qt::ApplicationModal);
+
+    // Clear mnemonic from local variables after dialog has copied it
+    const size_t mnemonic_size = mnemonic.size();
+    const size_t passphrase_size = mnemonic_passphrase.size();
+    mnemonic.assign(mnemonic_size, 0);
+    mnemonic_passphrase.assign(passphrase_size, 0);
+
+    verify_dialog.exec();
+
+    // UnlockContext destructor will automatically restore the wallet lock state
+}
+
 void WalletView::unlockWallet(bool fForMixingOnly)
 {
     // Unlock wallet when requested by wallet model

src/qt/walletview.h

@@ -107,6 +107,8 @@ public Q_SLOTS:
     void backupWallet();
     /** Change encrypted wallet passphrase */
     void changePassphrase();
+    /** Show wallet mnemonic/recovery phrase */
+    void showMnemonic();
     /** Ask for passphrase to unlock wallet temporarily */
     void unlockWallet(bool fAnonymizeOnly=false);
     /** Lock wallet */