]> gitweb.stoutner.com Git - PrivacyBrowserAndroid.git/blobdiff - app/src/main/java/com/stoutner/privacybrowser/activities/ImportExportActivity.java
Release 3.0.
[PrivacyBrowserAndroid.git] / app / src / main / java / com / stoutner / privacybrowser / activities / ImportExportActivity.java
index 26f2e1bc11bd4858cdc0c88bf88fd13eb294b093..4639c637ea83139f08253942a04013646e1b5e9d 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2018 Soren Stoutner <soren@stoutner.com>.
+ * Copyright © 2018-2019 Soren Stoutner <soren@stoutner.com>.
  *
  * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
  *
@@ -21,50 +21,90 @@ package com.stoutner.privacybrowser.activities;
 
 import android.Manifest;
 import android.app.Activity;
-import android.app.DialogFragment;
 import android.content.Intent;
+import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
+import android.media.MediaScannerConnection;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Environment;
+import android.os.Handler;
+import android.preference.PreferenceManager;
 import android.provider.DocumentsContract;
-import android.support.annotation.NonNull;
-import android.support.design.widget.Snackbar;
-import android.support.v4.app.ActivityCompat;
-import android.support.v4.content.ContextCompat;
-import android.support.v7.app.ActionBar;
-import android.support.v7.app.AppCompatActivity;
-import android.support.v7.widget.Toolbar;
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.view.View;
 import android.view.WindowManager;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
 import android.widget.Button;
 import android.widget.EditText;
+import android.widget.LinearLayout;
+import android.widget.RadioButton;
+import android.widget.Spinner;
 import android.widget.TextView;
 
+import androidx.annotation.NonNull;
+import androidx.appcompat.app.ActionBar;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar;
+import androidx.cardview.widget.CardView;
+import androidx.core.app.ActivityCompat;
+import androidx.core.content.ContextCompat;
+import androidx.core.content.FileProvider;
+import androidx.fragment.app.DialogFragment;
+
+import com.google.android.material.snackbar.Snackbar;
+import com.google.android.material.textfield.TextInputLayout;
+
 import com.stoutner.privacybrowser.R;
-import com.stoutner.privacybrowser.dialogs.ImportExportStoragePermissionDialog;
+import com.stoutner.privacybrowser.dialogs.StoragePermissionDialog;
 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
 
 import java.io.File;
-
-public class ImportExportActivity extends AppCompatActivity implements ImportExportStoragePermissionDialog.ImportExportStoragePermissionDialogListener {
-    private final static int EXPORT_FILE_PICKER_REQUEST_CODE = 1;
-    private final static int IMPORT_FILE_PICKER_REQUEST_CODE = 2;
-    private final static int EXPORT_REQUEST_CODE = 3;
-    private final static int IMPORT_REQUEST_CODE = 4;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.SecureRandom;
+import java.util.Arrays;
+
+import javax.crypto.Cipher;
+import javax.crypto.CipherInputStream;
+import javax.crypto.CipherOutputStream;
+import javax.crypto.spec.GCMParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+public class ImportExportActivity extends AppCompatActivity implements StoragePermissionDialog.StoragePermissionDialogListener {
+    // Create the encryption constants.
+    private final int NO_ENCRYPTION = 0;
+    private final int PASSWORD_ENCRYPTION = 1;
+    private final int OPENPGP_ENCRYPTION = 2;
+
+    // Create the activity result constants.
+    private final int BROWSE_RESULT_CODE = 0;
+    private final int OPENPGP_EXPORT_RESULT_CODE = 1;
+
+    // `openKeychainInstalled` is accessed from an inner class.
+    private boolean openKeychainInstalled;
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
+        // Get a handle for the shared preferences.
+        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
+
+        // Get the theme and screenshot preferences.
+        boolean darkTheme = sharedPreferences.getBoolean("dark_theme", false);
+        boolean allowScreenshots = sharedPreferences.getBoolean("allow_screenshots", false);
+
         // Disable screenshots if not allowed.
-        if (!MainWebViewActivity.allowScreenshots) {
+        if (!allowScreenshots) {
             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
         }
 
         // Set the activity theme.
-        if (MainWebViewActivity.darkTheme) {
+        if (darkTheme) {
             setTheme(R.style.PrivacyBrowserDark_SecondaryActivity);
         } else {
             setTheme(R.style.PrivacyBrowserLight_SecondaryActivity);
@@ -77,27 +117,197 @@ public class ImportExportActivity extends AppCompatActivity implements ImportExp
         setContentView(R.layout.import_export_coordinatorlayout);
 
         // Use the `SupportActionBar` from `android.support.v7.app.ActionBar` until the minimum API is >= 21.
-        Toolbar importExportAppBar = findViewById(R.id.import_export_toolbar);
-        setSupportActionBar(importExportAppBar);
+        Toolbar toolbar = findViewById(R.id.import_export_toolbar);
+        setSupportActionBar(toolbar);
+
+        // Get a handle for the action bar.
+        ActionBar actionBar = getSupportActionBar();
+
+        // Remove the incorrect lint warning that the action bar might be null.
+        assert actionBar != null;
 
         // Display the home arrow on the support action bar.
-        ActionBar appBar = getSupportActionBar();
-        assert appBar != null;// This assert removes the incorrect warning in Android Studio on the following line that `appBar` might be null.
-        appBar.setDisplayHomeAsUpEnabled(true);
+        actionBar.setDisplayHomeAsUpEnabled(true);
+
+        // Find out if we are running KitKat
+        boolean runningKitKat = (Build.VERSION.SDK_INT == 19);
+
+        // Find out if OpenKeychain is installed.
+        try {
+            openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
+        } catch (PackageManager.NameNotFoundException exception) {
+            openKeychainInstalled = false;
+        }
 
         // Get handles for the views that need to be modified.
-        EditText exportFileEditText = findViewById(R.id.export_file_edittext);
-        Button exportButton = findViewById(R.id.export_button);
-        EditText importFileEditText = findViewById(R.id.import_file_edittext);
-        Button importButton = findViewById(R.id.import_button);
+        Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
+        TextInputLayout passwordEncryptionTextInputLayout = findViewById(R.id.password_encryption_textinputlayout);
+        EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
+        TextView kitKatPasswordEncryptionTextView = findViewById(R.id.kitkat_password_encryption_textview);
+        TextView openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
+        CardView fileLocationCardView = findViewById(R.id.file_location_cardview);
+        RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
+        RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
+        LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
+        EditText fileNameEditText = findViewById(R.id.file_name_edittext);
+        TextView openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
+        Button importExportButton = findViewById(R.id.import_export_button);
         TextView storagePermissionTextView = findViewById(R.id.import_export_storage_permission_textview);
 
-        // Initially disable the buttons.
-        exportButton.setEnabled(false);
-        importButton.setEnabled(false);
+        // Create an array adapter for the spinner.
+        ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
+
+        // Set the drop down view resource on the spinner.
+        encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
+
+        // Set the array adapter for the spinner.
+        encryptionSpinner.setAdapter(encryptionArrayAdapter);
+
+        // Initially hide the unneeded views.
+        passwordEncryptionTextInputLayout.setVisibility(View.GONE);
+        kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
+        openKeychainRequiredTextView.setVisibility(View.GONE);
+        fileNameLinearLayout.setVisibility(View.GONE);
+        openKeychainImportInstructionsTextView.setVisibility(View.GONE);
+        importExportButton.setVisibility(View.GONE);
+
+        // Create strings for the default file paths.
+        String defaultFilePath;
+        String defaultPasswordEncryptionFilePath;
+
+        // Set the default file paths according to the storage permission status.
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
+            // Set the default file paths to use the external public directory.
+            defaultFilePath = Environment.getExternalStorageDirectory() + "/" + getString(R.string.settings_pbs);
+            defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
+        } else {  // The storage permission has not been granted.
+            // Set the default file paths to use the external private directory.
+            defaultFilePath = getApplicationContext().getExternalFilesDir(null) + "/" + getString(R.string.settings_pbs);
+            defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
+        }
+
+        // Set the default file path.
+        fileNameEditText.setText(defaultFilePath);
+
+        // Display the encryption information when the spinner changes.
+        encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
+            @Override
+            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
+                switch (position) {
+                    case NO_ENCRYPTION:
+                        // Hide the unneeded layout items.
+                        passwordEncryptionTextInputLayout.setVisibility(View.GONE);
+                        kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
+                        openKeychainRequiredTextView.setVisibility(View.GONE);
+                        openKeychainImportInstructionsTextView.setVisibility(View.GONE);
+
+                        // Show the file location card.
+                        fileLocationCardView.setVisibility(View.VISIBLE);
+
+                        // Show the file name linear layout if either import or export is checked.
+                        if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
+                            fileNameLinearLayout.setVisibility(View.VISIBLE);
+                        }
+
+                        // Reset the text of the import button, which may have been changed to `Decrypt`.
+                        if (importRadioButton.isChecked()) {
+                            importExportButton.setText(R.string.import_button);
+                        }
+
+                        // Reset the default file path.
+                        fileNameEditText.setText(defaultFilePath);
+
+                        // Enable the import/export button if a file name exists.
+                        importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
+                        break;
+
+                    case PASSWORD_ENCRYPTION:
+                        if (runningKitKat) {
+                            // Show the KitKat password encryption message.
+                            kitKatPasswordEncryptionTextView.setVisibility(View.VISIBLE);
+
+                            // Hide the OpenPGP required text view and the file location card.
+                            openKeychainRequiredTextView.setVisibility(View.GONE);
+                            fileLocationCardView.setVisibility(View.GONE);
+                        } else {
+                            // Hide the OpenPGP layout items.
+                            openKeychainRequiredTextView.setVisibility(View.GONE);
+                            openKeychainImportInstructionsTextView.setVisibility(View.GONE);
+
+                            // Show the password encryption layout items.
+                            passwordEncryptionTextInputLayout.setVisibility(View.VISIBLE);
+
+                            // Show the file location card.
+                            fileLocationCardView.setVisibility(View.VISIBLE);
+
+                            // Show the file name linear layout if either import or export is checked.
+                            if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
+                                fileNameLinearLayout.setVisibility(View.VISIBLE);
+                            }
+
+                            // Reset the text of the import button, which may have been changed to `Decrypt`.
+                            if (importRadioButton.isChecked()) {
+                                importExportButton.setText(R.string.import_button);
+                            }
+
+                            // Update the default file path.
+                            fileNameEditText.setText(defaultPasswordEncryptionFilePath);
+
+                            // Enable the import/export button if a password exists.
+                            importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
+                        }
+                        break;
+
+                    case OPENPGP_ENCRYPTION:
+                        // Hide the password encryption layout items.
+                        passwordEncryptionTextInputLayout.setVisibility(View.GONE);
+                        kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
+
+                        // Updated items based on the installation status of OpenKeychain.
+                        if (openKeychainInstalled) {  // OpenKeychain is installed.
+                            // Remove the default file path.
+                            fileNameEditText.setText("");
+
+                            // Show the file location card.
+                            fileLocationCardView.setVisibility(View.VISIBLE);
+
+                            if (importRadioButton.isChecked()) {
+                                // Show the file name linear layout and the OpenKeychain import instructions.
+                                fileNameLinearLayout.setVisibility(View.VISIBLE);
+                                openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
+
+                                // Set the text of the import button to be `Decrypt`.
+                                importExportButton.setText(R.string.decrypt);
+
+                                // Disable the import/export button.  The user needs to select a file to import first.
+                                importExportButton.setEnabled(false);
+                            } else if (exportRadioButton.isChecked()) {
+                                // Hide the file name linear layout and the OpenKeychain import instructions.
+                                fileNameLinearLayout.setVisibility(View.GONE);
+                                openKeychainImportInstructionsTextView.setVisibility(View.GONE);
+
+                                // Enable the import/export button.
+                                importExportButton.setEnabled(true);
+                            }
+                        } else {  // OpenKeychain is not installed.
+                            // Show the OpenPGP required layout item.
+                            openKeychainRequiredTextView.setVisibility(View.VISIBLE);
+
+                            // Hide the file location card.
+                            fileLocationCardView.setVisibility(View.GONE);
+                        }
+                        break;
+                }
+            }
 
-        // Enable the export button when the export file EditText isn't empty.
-        exportFileEditText.addTextChangedListener(new TextWatcher() {
+            @Override
+            public void onNothingSelected(AdapterView<?> parent) {
+
+            }
+        });
+
+        // Update the status of the import/export button when the password changes.
+        encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
             @Override
             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                 // Do nothing.
@@ -110,12 +320,13 @@ public class ImportExportActivity extends AppCompatActivity implements ImportExp
 
             @Override
             public void afterTextChanged(Editable s) {
-                exportButton.setEnabled(!exportFileEditText.getText().toString().isEmpty());
+                // Enable the import/export button if a file name and password exists.
+                importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
             }
         });
 
-        // Enable the import button when the export file EditText isn't empty.
-        importFileEditText.addTextChangedListener(new TextWatcher() {
+        // Update the status of the import/export button when the file name EditText changes.
+        fileNameEditText.addTextChangedListener(new TextWatcher() {
             @Override
             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                 // Do nothing.
@@ -128,353 +339,608 @@ public class ImportExportActivity extends AppCompatActivity implements ImportExp
 
             @Override
             public void afterTextChanged(Editable s) {
-                importButton.setEnabled(!importFileEditText.getText().toString().isEmpty());
+                // Adjust the export button according to the encryption spinner position.
+                switch (encryptionSpinner.getSelectedItemPosition()) {
+                    case NO_ENCRYPTION:
+                        // Enable the import/export button if a file name exists.
+                        importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
+                        break;
+
+                    case PASSWORD_ENCRYPTION:
+                        // Enable the import/export button if a file name and password exists.
+                        importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
+                        break;
+
+                    case OPENPGP_ENCRYPTION:
+                        // Enable the import/export button if OpenKeychain is installed and a file name exists.
+                        importExportButton.setEnabled(openKeychainInstalled && !fileNameEditText.getText().toString().isEmpty());
+                        break;
+                }
             }
         });
 
-        // Set the initial file paths.
-        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
-            // Create a string for the external public path.
-            String EXTERNAL_PUBLIC_PATH = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + getString(R.string.privacy_browser_settings);
-
-            // Set the default path.
-            exportFileEditText.setText(EXTERNAL_PUBLIC_PATH);
-            importFileEditText.setText(EXTERNAL_PUBLIC_PATH);
-        } else {  // The storage permission has not been granted.
-            // Create a string for the external private path.
-            String EXTERNAL_PRIVATE_PATH = getApplicationContext().getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS) + "/" + getString(R.string.privacy_browser_settings);
-
-            // Set the default path.
-            exportFileEditText.setText(EXTERNAL_PRIVATE_PATH);
-            importFileEditText.setText(EXTERNAL_PRIVATE_PATH);
-        }
-
-        // Hide the storage permissions TextView on API < 23 as permissions on older devices are automatically granted.
+        // Hide the storage permissions text view on API < 23 as permissions on older devices are automatically granted.
         if (Build.VERSION.SDK_INT < 23) {
             storagePermissionTextView.setVisibility(View.GONE);
         }
     }
 
-    public void exportBrowse(View view) {
-        // Create the file picker intent.
-        Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
+    public void onClickRadioButton(View view) {
+        // Get handles for the views.
+        Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
+        LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
+        EditText fileNameEditText = findViewById(R.id.file_name_edittext);
+        TextView openKeychainImportInstructionTextView = findViewById(R.id.openkeychain_import_instructions_textview);
+        Button importExportButton = findViewById(R.id.import_export_button);
+
+        // Check to see if import or export was selected.
+        switch (view.getId()) {
+            case R.id.import_radiobutton:
+                // Check to see if OpenPGP encryption is selected.
+                if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
+                    // Show the OpenKeychain import instructions.
+                    openKeychainImportInstructionTextView.setVisibility(View.VISIBLE);
+
+                    // Set the text on the import/export button to be `Decrypt`.
+                    importExportButton.setText(R.string.decrypt);
+
+                    // Enable the decrypt button if there is a file name.
+                    importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
+                } else {  // OpenPGP encryption not selected.
+                    // Hide the OpenKeychain import instructions.
+                    openKeychainImportInstructionTextView.setVisibility(View.GONE);
+
+                    // Set the text on the import/export button to be `Import`.
+                    importExportButton.setText(R.string.import_button);
+                }
+
+                // Display the file name views.
+                fileNameLinearLayout.setVisibility(View.VISIBLE);
+                importExportButton.setVisibility(View.VISIBLE);
+                break;
+
+            case R.id.export_radiobutton:
+                // Hide the OpenKeychain import instructions.
+                openKeychainImportInstructionTextView.setVisibility(View.GONE);
 
-        // Set the intent MIME type to include all files.
-        intent.setType("*/*");
+                // Set the text on the import/export button to be `Export`.
+                importExportButton.setText(R.string.export);
 
-        // Set the initial export file name.
-        intent.putExtra(Intent.EXTRA_TITLE, getString(R.string.privacy_browser_settings));
+                // Show the import/export button.
+                importExportButton.setVisibility(View.VISIBLE);
 
-        // Set the initial directory if API >= 26.
-        if (Build.VERSION.SDK_INT >= 26) {
-            intent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
+                // Check to see if OpenPGP encryption is selected.
+                if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
+                    // Hide the file name views.
+                    fileNameLinearLayout.setVisibility(View.GONE);
+
+                    // Enable the export button.
+                    importExportButton.setEnabled(true);
+                } else {  // OpenPGP encryption is not selected.
+                    // Show the file name views.
+                    fileNameLinearLayout.setVisibility(View.VISIBLE);
+                }
+                break;
         }
+    }
+
+    public void browse(View view) {
+        // Get a handle for the import radiobutton.
+        RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
+
+        // Check to see if import or export is selected.
+        if (importRadioButton.isChecked()) {  // Import is selected.
+            // Create the file picker intent.
+            Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
+
+            // Set the intent MIME type to include all files so that everything is visible.
+            importBrowseIntent.setType("*/*");
 
-        // Specify that a file that can be opened is requested.
-        intent.addCategory(Intent.CATEGORY_OPENABLE);
+            // Set the initial directory if the minimum API >= 26.
+            if (Build.VERSION.SDK_INT >= 26) {
+                importBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
+            }
+
+            // Request a file that can be opened.
+            importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
+
+            // Launch the file picker.
+            startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
+        } else {  // Export is selected
+            // Create the file picker intent.
+            Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
+
+            // Set the intent MIME type to include all files so that everything is visible.
+            exportBrowseIntent.setType("*/*");
+
+            // Set the initial export file name.
+            exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings_pbs));
+
+            // Set the initial directory if the minimum API >= 26.
+            if (Build.VERSION.SDK_INT >= 26) {
+                exportBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
+            }
 
-        // Launch the file picker.
-        startActivityForResult(intent, EXPORT_FILE_PICKER_REQUEST_CODE);
+            // Request a file that can be opened.
+            exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
+
+            // Launch the file picker.
+            startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
+        }
     }
 
-    public void onClickExport(View view) {
-        // Check to see if the storage permission has been granted.
-        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // Storage permission granted.
+    public void importExport(View view) {
+        // Get a handle for the views.
+        Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
+        RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
+        RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
+
+        // Check to see if the storage permission is needed.
+        if ((encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) && exportRadioButton.isChecked()) {  // Permission not needed to export via OpenKeychain.
             // Export the settings.
             exportSettings();
-        } else {  // Storage permission not granted.
-            // Get a handle for the export file EditText.
-            EditText exportFileEditText = findViewById(R.id.export_file_edittext);
+        } else if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
+            // Check to see if import or export is selected.
+            if (importRadioButton.isChecked()) {  // Import is selected.
+                // Import the settings.
+                importSettings();
+            } else {  // Export is selected.
+                // Export the settings.
+                exportSettings();
+            }
+        } else {  // The storage permission has not been granted.
+            // Get a handle for the file name EditText.
+            EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 
-            // Get the export file string.
-            String exportFileString = exportFileEditText.getText().toString();
+            // Get the file name string.
+            String fileNameString = fileNameEditText.getText().toString();
 
             // Get the external private directory `File`.
-            File externalPrivateDirectoryFile = getApplicationContext().getExternalFilesDir(null);
+            File externalPrivateDirectoryFile = getExternalFilesDir(null);
 
-            // Remove the lint error below that the `File` might be null.
+            // Remove the incorrect lint error below that the file might be null.
             assert externalPrivateDirectoryFile != null;
 
             // Get the external private directory string.
             String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
 
-            // Check to see if the export file path is in the external private directory.
-            if (exportFileString.startsWith(externalPrivateDirectory)) {  // The export path is in the external private directory.
-                // Export the settings.
-                exportSettings();
-            } else {  // The export path is in a public directory.
+            // Check to see if the file path is in the external private directory.
+            if (fileNameString.startsWith(externalPrivateDirectory)) {  // The file path is in the external private directory.
+                // Check to see if import or export is selected.
+                if (importRadioButton.isChecked()) {  // Import is selected.
+                    // Import the settings.
+                    importSettings();
+                } else {  // Export is selected.
+                    // Export the settings.
+                    exportSettings();
+                }
+            } else {  // The file path is in a public directory.
                 // Check if the user has previously denied the storage permission.
                 if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
-                    // Instantiate the storage permission alert dialog and set the type to EXPORT_SETTINGS.
-                    DialogFragment importExportStoragePermissionDialogFragment = ImportExportStoragePermissionDialog.type(ImportExportStoragePermissionDialog.EXPORT_SETTINGS);
+                    // Instantiate the storage permission alert dialog.
+                    DialogFragment storagePermissionDialogFragment = new StoragePermissionDialog();
 
                     // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
-                    importExportStoragePermissionDialogFragment.show(getFragmentManager(), getString(R.string.storage_permission));
+                    storagePermissionDialogFragment.show(getSupportFragmentManager(), getString(R.string.storage_permission));
                 } else {  // Show the permission request directly.
                     // Request the storage permission.  The export will be run when it finishes.
-                    ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, EXPORT_REQUEST_CODE);
+                    ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
                 }
             }
         }
     }
 
-    public void importBrowse(View view) {
-        // Create the file picker intent.
-        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
-
-        // Set the intent MIME type to include all files.
-        intent.setType("*/*");
-
-        // Set the initial directory if API >= 26.
-        if (Build.VERSION.SDK_INT >= 26) {
-            intent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
-        }
-
-        // Specify that a file that can be opened is requested.
-        intent.addCategory(Intent.CATEGORY_OPENABLE);
-
-        // Launch the file picker.
-        startActivityForResult(intent, IMPORT_FILE_PICKER_REQUEST_CODE);
+    @Override
+    public void onCloseStoragePermissionDialog() {
+        // Request the write external storage permission.  The import/export will be run when it finishes.
+        ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
     }
 
-    public void onClickImport(View view) {
-        // Check to see if the storage permission has been granted.
-        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // Storage permission granted.
-            // Import the settings.
-            importSettings();
-        } else {  // Storage permission not granted.
-            // Get a handle for the import file EditText.
-            EditText importFileEditText = findViewById(R.id.import_file_edittext);
-
-            // Get the import file string.
-            String importFileString = importFileEditText.getText().toString();
-
-            // Get the external private directory `File`.
-            File externalPrivateDirectoryFile = getApplicationContext().getExternalFilesDir(null);
-
-            // Remove the lint error below that `File` might be null.
-            assert externalPrivateDirectoryFile != null;
-
-            // Get the external private directory string.
-            String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
+    @Override
+    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
+        // Get a handle for the import radiobutton.
+        RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 
-            // Check to see if the import file path is in the external private directory.
-            if (importFileString.startsWith(externalPrivateDirectory)) {  // The import path is in the external private directory.
+        // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
+        if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
+            // Run the import or export methods according to which radio button is selected.
+            if (importRadioButton.isChecked()) {  // Import is selected.
                 // Import the settings.
                 importSettings();
-            } else {  // The import path is in a public directory.
-                // Check if the user has previously denied the storage permission.
-                if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
-                    // Instantiate the storage permission alert dialog and set the type to IMPORT_SETTINGS.
-                    DialogFragment importExportStoragePermissionDialogFragment = ImportExportStoragePermissionDialog.type(ImportExportStoragePermissionDialog.IMPORT_SETTINGS);
-
-                    // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
-                    importExportStoragePermissionDialogFragment.show(getFragmentManager(), getString(R.string.storage_permission));
-                } else {  // Show the permission request directly.
-                    // Request the storage permission.  The export will be run when it finishes.
-                    ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.READ_EXTERNAL_STORAGE}, IMPORT_REQUEST_CODE);
-                }
+            } else {  // Export is selected.
+                // Export the settings.
+                exportSettings();
             }
+        } else {  // The storage permission was not granted.
+            // Display an error snackbar.
+            Snackbar.make(importRadioButton, getString(R.string.cannot_use_location), Snackbar.LENGTH_LONG).show();
         }
     }
 
     @Override
     public void onActivityResult(int requestCode, int resultCode, Intent data) {
-        // Don't do anything if the user pressed back from the file picker.
-        if (resultCode == Activity.RESULT_OK) {
-            // Run the commands for the specific request code.
-            switch (requestCode) {
-                case EXPORT_FILE_PICKER_REQUEST_CODE:
-                    // Get a handle for the export file EditText.
-                    EditText exportFileEditText = findViewById(R.id.export_file_edittext);
+        switch (requestCode) {
+            case (BROWSE_RESULT_CODE):
+                // Don't do anything if the user pressed back from the file picker.
+                if (resultCode == Activity.RESULT_OK) {
+                    // Get a handle for the file name edit text.
+                    EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 
-                    // Get the selected export file.
-                    Uri exportUri = data.getData();
+                    // Get the file name URI.
+                    Uri fileNameUri = data.getData();
 
-                    // Remove the lint warning that the export URI might be null.
-                    assert exportUri != null;
+                    // Remove the lint warning that the file name URI might be null.
+                    assert fileNameUri != null;
 
-                    // Get the raw export path.
-                    String rawExportPath = exportUri.getPath();
+                    // Get the raw file name path.
+                    String rawFileNamePath = fileNameUri.getPath();
 
-                    // Remove the warning that the raw export path might be null.
-                    assert rawExportPath != null;
+                    // Remove the incorrect lint warning that the file name path might be null.
+                    assert rawFileNamePath != null;
 
-                    // Check to see if the rawExportPath includes a valid storage location.
-                    if (rawExportPath.contains(":")) {  // The path is valid.
-                        // Split the path into the initial content uri and the path information.
-                        String exportContentPath = rawExportPath.substring(0, rawExportPath.indexOf(":"));
-                        String exportFilePath = rawExportPath.substring(rawExportPath.indexOf(":") + 1);
+                    // Check to see if the file name Path includes a valid storage location.
+                    if (rawFileNamePath.contains(":")) {  // The path is valid.
+                        // Split the path into the initial content uri and the final path information.
+                        String fileNameContentPath = rawFileNamePath.substring(0, rawFileNamePath.indexOf(":"));
+                        String fileNameFinalPath = rawFileNamePath.substring(rawFileNamePath.indexOf(":") + 1);
 
-                        // Create the export path string.
-                        String exportPath;
+                        // Create the file name path string.
+                        String fileNamePath;
 
-                        // Construct the export path.
-                        switch (exportContentPath) {
+                        // Construct the file name path.
+                        switch (fileNameContentPath) {
                             // The documents home has a special content path.
                             case "/document/home":
-                                exportPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + exportFilePath;
+                                fileNamePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + fileNameFinalPath;
                                 break;
 
                             // Everything else for the primary user should be in `/document/primary`.
                             case "/document/primary":
-                                exportPath = Environment.getExternalStorageDirectory() + "/" + exportFilePath;
+                                fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
                                 break;
 
                             // Just in case, catch everything else and place it in the external storage directory.
                             default:
-                                exportPath = Environment.getExternalStorageDirectory() + "/" + exportFilePath;
+                                fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
                                 break;
                         }
 
-                        // Set the export file URI as the text for the export file EditText.
-                        exportFileEditText.setText(exportPath);
+                        // Set the file name path as the text of the file name EditText.
+                        fileNameEditText.setText(fileNamePath);
                     } else {  // The path is invalid.
-                        Snackbar.make(exportFileEditText, rawExportPath + " + " + getString(R.string.invalid_location), Snackbar.LENGTH_INDEFINITE).show();
+                        Snackbar.make(fileNameEditText, rawFileNamePath + " " + getString(R.string.invalid_location), Snackbar.LENGTH_INDEFINITE).show();
                     }
-                    break;
+                }
+                break;
 
-                case IMPORT_FILE_PICKER_REQUEST_CODE:
-                    // Get a handle for the import file EditText.
-                    EditText importFileEditText = findViewById(R.id.import_file_edittext);
+            case OPENPGP_EXPORT_RESULT_CODE:
+                // Get the temporary unencrypted export file.
+                File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 
-                    // Get the selected import file.
-                    Uri importUri = data.getData();
+                // Delete the temporary unencrypted export file if it exists.
+                if (temporaryUnencryptedExportFile.exists()) {
+                    //noinspection ResultOfMethodCallIgnored
+                    temporaryUnencryptedExportFile.delete();
+                }
+                break;
+        }
+    }
 
-                    // Remove the lint warning that the import URI might be null.
-                    assert importUri != null;
+    private void exportSettings() {
+        // Get a handle for the views.
+        Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
+        EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 
-                    // Get the raw import path.
-                    String rawImportPath = importUri.getPath();
+        // Instantiate the import export database helper.
+        ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 
-                    // Remove the warning that the raw import path might be null.
-                    assert rawImportPath != null;
+        // Get the export file string.
+        String exportFileString = fileNameEditText.getText().toString();
 
-                    // Check to see if the rawExportPath includes a valid storage location.
-                    if (rawImportPath.contains(":")) {  // The path is valid.
-                        // Split the path into the initial content uri and the path information.
-                        String importContentPath = rawImportPath.substring(0, rawImportPath.indexOf(":"));
-                        String importFilePath = rawImportPath.substring(rawImportPath.indexOf(":") + 1);
+        // Get the export and temporary unencrypted export files.
+        File exportFile = new File(exportFileString);
+        File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
+
+        // Create an export status string.
+        String exportStatus;
+
+        // Export according to the encryption type.
+        switch (encryptionSpinner.getSelectedItemPosition()) {
+            case NO_ENCRYPTION:
+                // Export the unencrypted file.
+                exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, this);
+
+                // Show a disposition snackbar.
+                if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
+                    Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
+                } else {
+                    Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
+                }
+                break;
 
-                        // Create the export path string.
-                        String importPath;
+            case PASSWORD_ENCRYPTION:
+                // Create an unencrypted export in a private directory.
+                exportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 
-                        // Construct the export path.
-                        switch (importContentPath) {
-                            // The documents folder has a special content path.
-                            case "/document/home":
-                                importPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + importFilePath;
-                                break;
+                try {
+                    // Create an unencrypted export file input stream.
+                    FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 
-                            // Everything else for the primary user should be in `/document/primary`.
-                            case "/document/primary":
-                                importPath = Environment.getExternalStorageDirectory() + "/" + importFilePath;
-                                break;
+                    // Delete the encrypted export file if it exists.
+                    if (exportFile.exists()) {
+                        //noinspection ResultOfMethodCallIgnored
+                        exportFile.delete();
+                    }
 
-                            // Just in case, catch everything else and place it in the external storage directory.
-                            default:
-                                importPath = Environment.getExternalStorageDirectory() + "/" + importFilePath;
-                                break;
-                        }
+                    // Create an encrypted export file output stream.
+                    FileOutputStream encryptedExportFileOutputStream = new FileOutputStream(exportFile);
 
-                        // Set the export file URI as the text for the export file EditText.
-                        importFileEditText.setText(importPath);
-                    } else {  // The path is invalid.
-                        Snackbar.make(importFileEditText, rawImportPath + " + " + getString(R.string.invalid_location), Snackbar.LENGTH_INDEFINITE).show();
+                    // Get a handle for the encryption password EditText.
+                    EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
+
+                    // Get the encryption password.
+                    String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
+
+                    // Initialize a secure random number generator.
+                    SecureRandom secureRandom = new SecureRandom();
+
+                    // Get a 256 bit (32 byte) random salt.
+                    byte[] saltByteArray = new byte[32];
+                    secureRandom.nextBytes(saltByteArray);
+
+                    // Convert the encryption password to a byte array.
+                    byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
+
+                    // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
+                    byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
+                    System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
+                    System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
+
+                    // Get a SHA-512 message digest.
+                    MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
+
+                    // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
+                    byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
+
+                    // Truncate the encryption password byte array to 256 bits (32 bytes).
+                    byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
+
+                    // Create an AES secret key from the encryption password byte array.
+                    SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
+
+                    // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
+                    byte[] initializationVector = new byte[12];
+                    secureRandom.nextBytes(initializationVector);
+
+                    // Get a Advanced Encryption Standard, Galois/Counter Mode, No Padding cipher instance. Galois/Counter mode protects against modification of the ciphertext.  It doesn't use padding.
+                    Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
+
+                    // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
+                    GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
+
+                    // Initialize the cipher.
+                    cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
+
+                    // Add the salt and the initialization vector to the export file.
+                    encryptedExportFileOutputStream.write(saltByteArray);
+                    encryptedExportFileOutputStream.write(initializationVector);
+
+                    // Create a cipher output stream.
+                    CipherOutputStream cipherOutputStream = new CipherOutputStream(encryptedExportFileOutputStream, cipher);
+
+                    // Initialize variables to store data as it is moved from the unencrypted export file input stream to the cipher output stream.  Move 128 bits (16 bytes) at a time.
+                    int numberOfBytesRead;
+                    byte[] encryptedBytes = new byte[16];
+
+                    // Read up to 128 bits (16 bytes) of data from the unencrypted export file stream.  `-1` will be returned when the end of the file is reached.
+                    while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
+                        // Write the data to the cipher output stream.
+                        cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
                     }
-                    break;
-            }
-        }
-    }
 
-    @Override
-    public void onCloseImportExportStoragePermissionDialog(int type) {
-        // Request the storage permission based on the button that was pressed.
-        switch (type) {
-            case ImportExportStoragePermissionDialog.EXPORT_SETTINGS:
-                // Request the storage permission.  The export will be run when it finishes.
-                ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, EXPORT_REQUEST_CODE);
+                    // Close the streams.
+                    cipherOutputStream.flush();
+                    cipherOutputStream.close();
+                    encryptedExportFileOutputStream.close();
+                    unencryptedExportFileInputStream.close();
+
+                    // Wipe the encryption data from memory.
+                    //noinspection UnusedAssignment
+                    encryptionPasswordString = "";
+                    Arrays.fill(saltByteArray, (byte) 0);
+                    Arrays.fill(encryptionPasswordByteArray, (byte) 0);
+                    Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
+                    Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
+                    Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
+                    Arrays.fill(initializationVector, (byte) 0);
+                    Arrays.fill(encryptedBytes, (byte) 0);
+
+                    // Delete the temporary unencrypted export file.
+                    //noinspection ResultOfMethodCallIgnored
+                    temporaryUnencryptedExportFile.delete();
+                } catch (Exception exception) {
+                    exportStatus = exception.toString();
+                }
+
+                // Show a disposition snackbar.
+                if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
+                    Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
+                } else {
+                    Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
+                }
                 break;
 
-            case ImportExportStoragePermissionDialog.IMPORT_SETTINGS:
-                // Request the storage permission.  The import will be run when it finishes.
-                ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.READ_EXTERNAL_STORAGE}, IMPORT_REQUEST_CODE);
+            case OPENPGP_ENCRYPTION:
+                // Create an unencrypted export in the private location.
+                importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
+
+                // Create an encryption intent for OpenKeychain.
+                Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
+
+                // Include the temporary unencrypted export file URI.
+                openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryUnencryptedExportFile));
+
+                // Allow OpenKeychain to read the file URI.
+                openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+
+                // Send the intent to the OpenKeychain package.
+                openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
+
+                // Make it so.
+                startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
                 break;
         }
+
+        // Add the file to the list of recent files.  This doesn't currently work, but maybe it will someday.
+        MediaScannerConnection.scanFile(this, new String[] {exportFileString}, new String[] {"application/x-sqlite3"}, null);
     }
 
-    @Override
-    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
-        switch (requestCode) {
-            case EXPORT_REQUEST_CODE:
-                // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
-                if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
-                    // Export the settings.
-                    exportSettings();
-                } else {  // The storage permission was not granted.
-                    // Get a handle for the export file EditText.
-                    EditText exportFileEditText = findViewById(R.id.export_file_edittext);
+    private void importSettings() {
+        // Get a handle for the views.
+        Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
+        EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 
-                    // Display an error snackbar.
-                    Snackbar.make(exportFileEditText, getString(R.string.cannot_export), Snackbar.LENGTH_LONG).show();
-                }
-                break;
+        // Instantiate the import export database helper.
+        ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 
-            case IMPORT_REQUEST_CODE:
-                // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
-                if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
-                    // Import the settings.
-                    importSettings();
-                } else {  // The storage permission was not granted.
-                    // Get a handle for the import file EditText.
-                    EditText importFileEditText = findViewById(R.id.import_file_edittext);
+        // Get the import file.
+        File importFile = new File(fileNameEditText.getText().toString());
 
-                    // Display an error snackbar.
-                    Snackbar.make(importFileEditText, getString(R.string.cannot_import), Snackbar.LENGTH_LONG).show();
-                }
+        // Initialize the import status string
+        String importStatus = "";
+
+        // Import according to the encryption type.
+        switch (encryptionSpinner.getSelectedItemPosition()) {
+            case NO_ENCRYPTION:
+                // Import the unencrypted file.
+                importStatus = importExportDatabaseHelper.importUnencrypted(importFile, this);
                 break;
-        }
-    }
 
-    private void exportSettings() {
-        // Get a handle for the export file EditText.
-        EditText exportFileEditText = findViewById(R.id.export_file_edittext);
+            case PASSWORD_ENCRYPTION:
+                // Use a private temporary import location.
+                File temporaryUnencryptedImportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 
-        // Get the export file string.
-        String exportFileString = exportFileEditText.getText().toString();
+                try {
+                    // Create an encrypted import file input stream.
+                    FileInputStream encryptedImportFileInputStream = new FileInputStream(importFile);
 
-        // Set the export file.
-        File exportFile = new File(exportFileString);
+                    // Delete the temporary import file if it exists.
+                    if (temporaryUnencryptedImportFile.exists()) {
+                        //noinspection ResultOfMethodCallIgnored
+                        temporaryUnencryptedImportFile.delete();
+                    }
 
-        // Instantiate the import export database helper.
-        ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
+                    // Create an unencrypted import file output stream.
+                    FileOutputStream unencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 
-        // Export the unencrypted file.
-        String exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, getApplicationContext());
+                    // Get a handle for the encryption password EditText.
+                    EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 
-        // Show a disposition snackbar.
-        if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
-            Snackbar.make(exportFileEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
-        } else {
-            Snackbar.make(exportFileEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
-        }
-    }
+                    // Get the encryption password.
+                    String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 
-    private void importSettings() {
-        // Get a handle for the import file EditText.
-        EditText importFileEditText = findViewById(R.id.import_file_edittext);
+                    // Get the salt from the beginning of the import file.
+                    byte[] saltByteArray = new byte[32];
+                    //noinspection ResultOfMethodCallIgnored
+                    encryptedImportFileInputStream.read(saltByteArray);
 
-        // Get the import file string.
-        String importFileString = importFileEditText.getText().toString();
+                    // Get the initialization vector from the import file.
+                    byte[] initializationVector = new byte[12];
+                    //noinspection ResultOfMethodCallIgnored
+                    encryptedImportFileInputStream.read(initializationVector);
 
-        // Set the import file.
-        File importFile = new File(importFileString);
+                    // Convert the encryption password to a byte array.
+                    byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 
-        // Instantiate the import export database helper.
-        ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
+                    // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
+                    byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
+                    System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
+                    System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
+
+                    // Get a SHA-512 message digest.
+                    MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
+
+                    // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
+                    byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
+
+                    // Truncate the encryption password byte array to 256 bits (32 bytes).
+                    byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
+
+                    // Create an AES secret key from the encryption password byte array.
+                    SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
+
+                    // Get a Advanced Encryption Standard, Galois/Counter Mode, No Padding cipher instance. Galois/Counter mode protects against modification of the ciphertext.  It doesn't use padding.
+                    Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 
-        // Import the unencrypted file.
-        String importStatus = importExportDatabaseHelper.importUnencrypted(importFile, getApplicationContext());
+                    // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
+                    GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
+
+                    // Initialize the cipher.
+                    cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
+
+                    // Create a cipher input stream.
+                    CipherInputStream cipherInputStream = new CipherInputStream(encryptedImportFileInputStream, cipher);
+
+                    // Initialize variables to store data as it is moved from the cipher input stream to the unencrypted import file output stream.  Move 128 bits (16 bytes) at a time.
+                    int numberOfBytesRead;
+                    byte[] decryptedBytes = new byte[16];
+
+                    // Read up to 128 bits (16 bytes) of data from the cipher input stream.  `-1` will be returned when the end fo the file is reached.
+                    while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
+                        // Write the data to the unencrypted import file output stream.
+                        unencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
+                    }
+
+                    // Close the streams.
+                    unencryptedImportFileOutputStream.flush();
+                    unencryptedImportFileOutputStream.close();
+                    cipherInputStream.close();
+                    encryptedImportFileInputStream.close();
+
+                    // Wipe the encryption data from memory.
+                    //noinspection UnusedAssignment
+                    encryptionPasswordString = "";
+                    Arrays.fill(saltByteArray, (byte) 0);
+                    Arrays.fill(initializationVector, (byte) 0);
+                    Arrays.fill(encryptionPasswordByteArray, (byte) 0);
+                    Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
+                    Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
+                    Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
+                    Arrays.fill(decryptedBytes, (byte) 0);
+
+                    // Import the unencrypted database from the private location.
+                    importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFile, this);
+
+                    // Delete the temporary unencrypted import file.
+                    //noinspection ResultOfMethodCallIgnored
+                    temporaryUnencryptedImportFile.delete();
+                } catch (Exception exception) {
+                    importStatus = exception.toString();
+                }
+                break;
+
+            case OPENPGP_ENCRYPTION:
+                try {
+                    // Create an decryption intent for OpenKeychain.
+                    Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
+
+                    // Include the URI to be decrypted.
+                    openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), importFile));
+
+                    // Allow OpenKeychain to read the file URI.
+                    openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+
+                    // Send the intent to the OpenKeychain package.
+                    openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
+
+                    // Make it so.
+                    startActivity(openKeychainDecryptIntent);
+                } catch (IllegalArgumentException exception) {  // The file import location is not valid.
+                    // Display a snack bar with the import error.
+                    Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + exception.toString(), Snackbar.LENGTH_INDEFINITE).show();
+                }
+                break;
+        }
 
         // Respond to the import disposition.
         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {  // The import was successful.
@@ -487,11 +953,24 @@ public class ImportExportActivity extends AppCompatActivity implements ImportExp
             // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
             restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 
-            // Make it so.
-            startActivity(restartIntent);
-        } else {  // The import was not successful.
+            // Create a restart handler.
+            Handler restartHandler = new Handler();
+
+            // Create a restart runnable.
+            Runnable restartRunnable =  () -> {
+                // Restart Privacy Browser.
+                startActivity(restartIntent);
+
+                // Kill this instance of Privacy Browser.  Otherwise, the app exhibits sporadic behavior after the restart.
+                System.exit(0);
+            };
+
+            // Restart Privacy Browser after 100 milliseconds to allow enough time for the preferences to be saved.
+            restartHandler.postDelayed(restartRunnable, 100);
+
+        } else if (!(encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION)){  // The import was not successful.
             // Display a snack bar with the import error.
-            Snackbar.make(importFileEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
+            Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
         }
     }
 }
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