app/src/main/java/com/stoutner/privacybrowser/activities/ImportExportActivity.java

   1 /*
   2  * Copyright © 2018-2021 Soren Stoutner <soren@stoutner.com>.
   3  *
   4  * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
   5  *
   6  * Privacy Browser is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * Privacy Browser is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 package com.stoutner.privacybrowser.activities;
  21
  22 import android.app.Activity;
  23 import android.content.Intent;
  24 import android.content.SharedPreferences;
  25 import android.content.pm.PackageManager;
  26 import android.net.Uri;
  27 import android.os.Build;
  28 import android.os.Bundle;
  29 import android.os.Handler;
  30 import android.preference.PreferenceManager;
  31 import android.text.Editable;
  32 import android.text.TextWatcher;
  33 import android.view.View;
  34 import android.view.WindowManager;
  35 import android.widget.AdapterView;
  36 import android.widget.ArrayAdapter;
  37 import android.widget.Button;
  38 import android.widget.EditText;
  39 import android.widget.LinearLayout;
  40 import android.widget.RadioButton;
  41 import android.widget.Spinner;
  42 import android.widget.TextView;
  43
  44 import androidx.annotation.NonNull;
  45 import androidx.appcompat.app.ActionBar;
  46 import androidx.appcompat.app.AppCompatActivity;
  47 import androidx.appcompat.widget.Toolbar;
  48 import androidx.cardview.widget.CardView;
  49 import androidx.core.content.FileProvider;
  50
  51 import com.google.android.material.snackbar.Snackbar;
  52 import com.google.android.material.textfield.TextInputLayout;
  53
  54 import com.stoutner.privacybrowser.BuildConfig;
  55 import com.stoutner.privacybrowser.R;
  56 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  57
  58 import java.io.File;
  59 import java.io.FileInputStream;
  60 import java.io.FileNotFoundException;
  61 import java.io.FileOutputStream;
  62 import java.io.InputStream;
  63 import java.io.OutputStream;
  64 import java.nio.charset.StandardCharsets;
  65 import java.security.MessageDigest;
  66 import java.security.SecureRandom;
  67 import java.util.Arrays;
  68
  69 import javax.crypto.Cipher;
  70 import javax.crypto.CipherInputStream;
  71 import javax.crypto.CipherOutputStream;
  72 import javax.crypto.spec.GCMParameterSpec;
  73 import javax.crypto.spec.SecretKeySpec;
  74
  75 public class ImportExportActivity extends AppCompatActivity {
  76     // Define the encryption constants.
  77     private final int NO_ENCRYPTION = 0;
  78     private final int PASSWORD_ENCRYPTION = 1;
  79     private final int OPENPGP_ENCRYPTION = 2;
  80
  81     // Define the activity result constants.
  82     private final int BROWSE_RESULT_CODE = 0;
  83     private final int OPENPGP_IMPORT_RESULT_CODE = 1;
  84     private final int OPENPGP_EXPORT_RESULT_CODE = 2;
  85
  86     // Define the saved instance state constants.
  87     private final String ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY = "encryption_password_textinputlayout_visibility";
  88     private final String KITKAT_PASSWORD_ENCRYPTED_TEXTVIEW_VISIBILITY = "kitkat_password_encrypted_textview_visibility";
  89     private final String OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY = "open_keychain_required_textview_visibility";
  90     private final String FILE_LOCATION_CARD_VIEW = "file_location_card_view";
  91     private final String FILE_NAME_LINEARLAYOUT_VISIBILITY = "file_name_linearlayout_visibility";
  92     private final String OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY = "open_keychain_import_instructions_textview_visibility";
  93     private final String IMPORT_EXPORT_BUTTON_VISIBILITY = "import_export_button_visibility";
  94     private final String FILE_NAME_TEXT = "file_name_text";
  95     private final String IMPORT_EXPORT_BUTTON_TEXT = "import_export_button_text";
  96
  97     // Define the class views.
  98     Spinner encryptionSpinner;
  99     TextInputLayout encryptionPasswordTextInputLayout;
 100     EditText encryptionPasswordEditText;
 101     TextView kitKatPasswordEncryptionTextView;
 102     TextView openKeychainRequiredTextView;
 103     CardView fileLocationCardView;
 104     RadioButton importRadioButton;
 105     LinearLayout fileNameLinearLayout;
 106     EditText fileNameEditText;
 107     TextView openKeychainImportInstructionsTextView;
 108     Button importExportButton;
 109
 110     // Define the class variables.
 111     private boolean openKeychainInstalled;
 112     private File temporaryPgpEncryptedImportFile;
 113     private File temporaryPreEncryptedExportFile;
 114
 115     @Override
 116     public void onCreate(Bundle savedInstanceState) {
 117         // Get a handle for the shared preferences.
 118         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
 119
 120         // Get the screenshot preference.
 121         boolean allowScreenshots = sharedPreferences.getBoolean("allow_screenshots", false);
 122
 123         // Disable screenshots if not allowed.
 124         if (!allowScreenshots) {
 125             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
 126         }
 127
 128         // Set the theme.
 129         setTheme(R.style.PrivacyBrowser);
 130
 131         // Run the default commands.
 132         super.onCreate(savedInstanceState);
 133
 134         // Set the content view.
 135         setContentView(R.layout.import_export_coordinatorlayout);
 136
 137         // Set the support action bar.
 138         Toolbar toolbar = findViewById(R.id.import_export_toolbar);
 139         setSupportActionBar(toolbar);
 140
 141         // Get a handle for the action bar.
 142         ActionBar actionBar = getSupportActionBar();
 143
 144         // Remove the incorrect lint warning that the action bar might be null.
 145         assert actionBar != null;
 146
 147         // Display the home arrow on the support action bar.
 148         actionBar.setDisplayHomeAsUpEnabled(true);
 149
 150         // Find out if the system is running KitKat
 151         boolean runningKitKat = (Build.VERSION.SDK_INT == 19);
 152
 153         // Find out if OpenKeychain is installed.
 154         try {
 155             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 156         } catch (PackageManager.NameNotFoundException exception) {
 157             openKeychainInstalled = false;
 158         }
 159
 160         // Get handles for the views that need to be modified.
 161         encryptionSpinner = findViewById(R.id.encryption_spinner);
 162         encryptionPasswordTextInputLayout = findViewById(R.id.encryption_password_textinputlayout);
 163         encryptionPasswordEditText = findViewById(R.id.encryption_password_edittext);
 164         kitKatPasswordEncryptionTextView = findViewById(R.id.kitkat_password_encryption_textview);
 165         openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
 166         fileLocationCardView = findViewById(R.id.file_location_cardview);
 167         importRadioButton = findViewById(R.id.import_radiobutton);
 168         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 169         fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 170         fileNameEditText = findViewById(R.id.file_name_edittext);
 171         openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 172         importExportButton = findViewById(R.id.import_export_button);
 173
 174         // Create an array adapter for the spinner.
 175         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 176
 177         // Set the drop down view resource on the spinner.
 178         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 179
 180         // Set the array adapter for the spinner.
 181         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 182
 183         // Update the UI when the spinner changes.
 184         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 185             @Override
 186             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 187                 switch (position) {
 188                     case NO_ENCRYPTION:
 189                         // Hide the unneeded layout items.
 190                         encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 191                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 192                         openKeychainRequiredTextView.setVisibility(View.GONE);
 193                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 194
 195                         // Show the file location card.
 196                         fileLocationCardView.setVisibility(View.VISIBLE);
 197
 198                         // Show the file name linear layout if either import or export is checked.
 199                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 200                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 201                         }
 202
 203                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 204                         if (importRadioButton.isChecked()) {
 205                             importExportButton.setText(R.string.import_button);
 206                         }
 207
 208                         // Enable the import/export button if the file name is populated.
 209                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 210                         break;
 211
 212                     case PASSWORD_ENCRYPTION:
 213                         if (runningKitKat) {
 214                             // Show the KitKat password encryption message.
 215                             kitKatPasswordEncryptionTextView.setVisibility(View.VISIBLE);
 216
 217                             // Hide the OpenPGP required text view and the file location card.
 218                             openKeychainRequiredTextView.setVisibility(View.GONE);
 219                             fileLocationCardView.setVisibility(View.GONE);
 220                         } else {
 221                             // Hide the OpenPGP layout items.
 222                             openKeychainRequiredTextView.setVisibility(View.GONE);
 223                             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 224
 225                             // Show the password encryption layout items.
 226                             encryptionPasswordTextInputLayout.setVisibility(View.VISIBLE);
 227
 228                             // Show the file location card.
 229                             fileLocationCardView.setVisibility(View.VISIBLE);
 230
 231                             // Show the file name linear layout if either import or export is checked.
 232                             if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 233                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 234                             }
 235
 236                             // Reset the text of the import button, which may have been changed to `Decrypt`.
 237                             if (importRadioButton.isChecked()) {
 238                                 importExportButton.setText(R.string.import_button);
 239                             }
 240
 241                             // Enable the import/button if both the password and the file name are populated.
 242                             importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 243                         }
 244                         break;
 245
 246                     case OPENPGP_ENCRYPTION:
 247                         // Hide the password encryption layout items.
 248                         encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 249                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 250
 251                         // Updated items based on the installation status of OpenKeychain.
 252                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 253                             // Show the file location card.
 254                             fileLocationCardView.setVisibility(View.VISIBLE);
 255
 256                             if (importRadioButton.isChecked()) {
 257                                 // Show the file name linear layout and the OpenKeychain import instructions.
 258                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 259                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 260
 261                                 // Set the text of the import button to be `Decrypt`.
 262                                 importExportButton.setText(R.string.decrypt);
 263
 264                                 // Enable the import button if the file name is populated.
 265                                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 266                             } else if (exportRadioButton.isChecked()) {
 267                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 268                                 fileNameLinearLayout.setVisibility(View.GONE);
 269                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 270
 271                                 // Enable the export button.
 272                                 importExportButton.setEnabled(true);
 273                             }
 274                         } else {  // OpenKeychain is not installed.
 275                             // Show the OpenPGP required layout item.
 276                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 277
 278                             // Hide the file location card.
 279                             fileLocationCardView.setVisibility(View.GONE);
 280                         }
 281                         break;
 282                 }
 283             }
 284
 285             @Override
 286             public void onNothingSelected(AdapterView<?> parent) {
 287
 288             }
 289         });
 290
 291         // Update the status of the import/export button when the password changes.
 292         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 293             @Override
 294             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 295                 // Do nothing.
 296             }
 297
 298             @Override
 299             public void onTextChanged(CharSequence s, int start, int before, int count) {
 300                 // Do nothing.
 301             }
 302
 303             @Override
 304             public void afterTextChanged(Editable s) {
 305                 // Enable the import/export button if both the file string and the password are populated.
 306                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 307             }
 308         });
 309
 310         // Update the UI when the file name EditText changes.
 311         fileNameEditText.addTextChangedListener(new TextWatcher() {
 312             @Override
 313             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 314                 // Do nothing.
 315             }
 316
 317             @Override
 318             public void onTextChanged(CharSequence s, int start, int before, int count) {
 319                 // Do nothing.
 320             }
 321
 322             @Override
 323             public void afterTextChanged(Editable s) {
 324                 // Adjust the UI according to the encryption spinner position.
 325                 if (encryptionSpinner.getSelectedItemPosition() == PASSWORD_ENCRYPTION) {
 326                     // Enable the import/export button if both the file name and the password are populated.
 327                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 328                 } else {
 329                     // Enable the export button if the file name is populated.
 330                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 331                 }
 332             }
 333         });
 334
 335         // Check to see if the activity has been restarted.
 336         if (savedInstanceState == null) {  // The app has not been restarted.
 337             // Initially hide the unneeded views.
 338             encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 339             kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 340             openKeychainRequiredTextView.setVisibility(View.GONE);
 341             fileNameLinearLayout.setVisibility(View.GONE);
 342             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 343             importExportButton.setVisibility(View.GONE);
 344         } else {  // The app has been restarted.
 345             // Restore the visibility of the views.
 346             encryptionPasswordTextInputLayout.setVisibility(savedInstanceState.getInt(ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY));
 347             kitKatPasswordEncryptionTextView.setVisibility(savedInstanceState.getInt(KITKAT_PASSWORD_ENCRYPTED_TEXTVIEW_VISIBILITY));
 348             openKeychainRequiredTextView.setVisibility(savedInstanceState.getInt(OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY));
 349             fileLocationCardView.setVisibility(savedInstanceState.getInt(FILE_LOCATION_CARD_VIEW));
 350             fileNameLinearLayout.setVisibility(savedInstanceState.getInt(FILE_NAME_LINEARLAYOUT_VISIBILITY));
 351             openKeychainImportInstructionsTextView.setVisibility(savedInstanceState.getInt(OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY));
 352             importExportButton.setVisibility(savedInstanceState.getInt(IMPORT_EXPORT_BUTTON_VISIBILITY));
 353
 354             // Restore the text.
 355             fileNameEditText.post(() -> fileNameEditText.setText(savedInstanceState.getString(FILE_NAME_TEXT)));
 356             importExportButton.setText(savedInstanceState.getString(IMPORT_EXPORT_BUTTON_TEXT));
 357         }
 358     }
 359
 360     @Override
 361     public void onSaveInstanceState (@NonNull Bundle savedInstanceState) {
 362         // Run the default commands.
 363         super.onSaveInstanceState(savedInstanceState);
 364
 365         // Save the visibility of the views.
 366         savedInstanceState.putInt(ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY, encryptionPasswordTextInputLayout.getVisibility());
 367         savedInstanceState.putInt(KITKAT_PASSWORD_ENCRYPTED_TEXTVIEW_VISIBILITY, kitKatPasswordEncryptionTextView.getVisibility());
 368         savedInstanceState.putInt(OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY, openKeychainRequiredTextView.getVisibility());
 369         savedInstanceState.putInt(FILE_LOCATION_CARD_VIEW, fileLocationCardView.getVisibility());
 370         savedInstanceState.putInt(FILE_NAME_LINEARLAYOUT_VISIBILITY, fileNameLinearLayout.getVisibility());
 371         savedInstanceState.putInt(OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY, openKeychainImportInstructionsTextView.getVisibility());
 372         savedInstanceState.putInt(IMPORT_EXPORT_BUTTON_VISIBILITY, importExportButton.getVisibility());
 373
 374         // Save the text.
 375         savedInstanceState.putString(FILE_NAME_TEXT, fileNameEditText.getText().toString());
 376         savedInstanceState.putString(IMPORT_EXPORT_BUTTON_TEXT, importExportButton.getText().toString());
 377     }
 378
 379     public void onClickRadioButton(View view) {
 380         // Get the current file name.
 381         String fileNameString = fileNameEditText.getText().toString();
 382
 383         // Convert the file name string to a file.
 384         File file = new File(fileNameString);
 385
 386         // Check to see if import or export was selected.
 387         if (view.getId() == R.id.import_radiobutton) {  // The import radio button is selected.
 388             // Check to see if OpenPGP encryption is selected.
 389             if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 390                 // Show the OpenKeychain import instructions.
 391                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 392
 393                 // Set the text on the import/export button to be `Decrypt`.
 394                 importExportButton.setText(R.string.decrypt);
 395             } else {  // OpenPGP encryption not selected.
 396                 // Hide the OpenKeychain import instructions.
 397                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 398
 399                 // Set the text on the import/export button to be `Import`.
 400                 importExportButton.setText(R.string.import_button);
 401             }
 402
 403             // Display the file name views.
 404             fileNameLinearLayout.setVisibility(View.VISIBLE);
 405             importExportButton.setVisibility(View.VISIBLE);
 406
 407             // Check to see if the file exists.
 408             if (file.exists()) {  // The file exists.
 409                 // Check to see if password encryption is selected.
 410                 if (encryptionSpinner.getSelectedItemPosition() == PASSWORD_ENCRYPTION) {  // Password encryption is selected.
 411                     // Enable the import button if the encryption password is populated.
 412                     importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 413                 } else {  // Password encryption is not selected.
 414                     // Enable the import/decrypt button.
 415                     importExportButton.setEnabled(true);
 416                 }
 417             } else {  // The file does not exist.
 418                 // Disable the import/decrypt button.
 419                 importExportButton.setEnabled(false);
 420             }
 421         } else {  // The export radio button is selected.
 422             // Hide the OpenKeychain import instructions.
 423             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 424
 425             // Set the text on the import/export button to be `Export`.
 426             importExportButton.setText(R.string.export);
 427
 428             // Show the import/export button.
 429             importExportButton.setVisibility(View.VISIBLE);
 430
 431             // Check to see if OpenPGP encryption is selected.
 432             if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 433                 // Hide the file name views.
 434                 fileNameLinearLayout.setVisibility(View.GONE);
 435
 436                 // Enable the export button.
 437                 importExportButton.setEnabled(true);
 438             } else {  // OpenPGP encryption is not selected.
 439                 // Show the file name view.
 440                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 441
 442                 // Check the encryption type.
 443                 if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 444                     // Enable the export button if the file name is populated.
 445                     importExportButton.setEnabled(!fileNameString.isEmpty());
 446                 } else {  // Password encryption is selected.
 447                     // Enable the export button if the file name and the password are populated.
 448                     importExportButton.setEnabled(!fileNameString.isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 449                 }
 450             }
 451         }
 452     }
 453
 454     public void browse(View view) {
 455         // Check to see if import or export is selected.
 456         if (importRadioButton.isChecked()) {  // Import is selected.
 457             // Create the file picker intent.
 458             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 459
 460             // Set the intent MIME type to include all files so that everything is visible.
 461             importBrowseIntent.setType("*/*");
 462
 463             // Request a file that can be opened.
 464             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 465
 466             // Launch the file picker.
 467             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 468         } else {  // Export is selected
 469             // Create the file picker intent.
 470             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 471
 472             // Set the intent MIME type to include all files so that everything is visible.
 473             exportBrowseIntent.setType("*/*");
 474
 475             // Set the initial export file name according to the encryption type.
 476             if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 477                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs");
 478             } else {  // Password encryption is selected.
 479                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs.aes");
 480             }
 481
 482             // Request a file that can be opened.
 483             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 484
 485             // Launch the file picker.
 486             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 487         }
 488     }
 489
 490     @Override
 491     public void onActivityResult(int requestCode, int resultCode, Intent returnedIntent) {
 492         // Run the default commands.
 493         super.onActivityResult(requestCode, resultCode, returnedIntent);
 494
 495         switch (requestCode) {
 496             case (BROWSE_RESULT_CODE):
 497                 // Only do something if the user didn't press back from the file picker.
 498                 if (resultCode == Activity.RESULT_OK) {
 499                     // Get the file path URI from the intent.
 500                     Uri fileNameUri = returnedIntent.getData();
 501
 502                     // Get the file name string from the URI.
 503                     String fileNameString = fileNameUri.toString();
 504
 505                     // Set the file name name text.
 506                     fileNameEditText.setText(fileNameString);
 507
 508                     // Move the cursor to the end of the file name edit text.
 509                     fileNameEditText.setSelection(fileNameString.length());
 510                 }
 511                 break;
 512
 513             case OPENPGP_IMPORT_RESULT_CODE:
 514                 // Delete the temporary PGP encrypted import file.
 515                 if (temporaryPgpEncryptedImportFile.exists()) {
 516                     //noinspection ResultOfMethodCallIgnored
 517                     temporaryPgpEncryptedImportFile.delete();
 518                 }
 519                 break;
 520
 521             case OPENPGP_EXPORT_RESULT_CODE:
 522                 // Delete the temporary pre-encrypted export file if it exists.
 523                 if (temporaryPreEncryptedExportFile.exists()) {
 524                     //noinspection ResultOfMethodCallIgnored
 525                     temporaryPreEncryptedExportFile.delete();
 526                 }
 527                 break;
 528         }
 529     }
 530
 531     public void importExport(View view) {
 532         // Instantiate the import export database helper.
 533         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 534
 535         // Check to see if import or export is selected.
 536         if (importRadioButton.isChecked()) {  // Import is selected.
 537             // Initialize the import status string
 538             String importStatus = "";
 539
 540             // Get the file name string.
 541             String fileNameString = fileNameEditText.getText().toString();
 542
 543             // Import according to the encryption type.
 544             switch (encryptionSpinner.getSelectedItemPosition()) {
 545                 case NO_ENCRYPTION:
 546                     try {
 547                         // Get an input stream for the file name.
 548                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 549
 550                         // Import the unencrypted file.
 551                         importStatus = importExportDatabaseHelper.importUnencrypted(inputStream, this);
 552                     } catch (FileNotFoundException exception) {
 553                         // Update the import status.
 554                         importStatus = exception.toString();
 555                     }
 556
 557                     // Restart Privacy Browser if successful.
 558                     if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 559                         restartPrivacyBrowser();
 560                     }
 561                     break;
 562
 563                 case PASSWORD_ENCRYPTION:
 564                     try {
 565                         // Get the encryption password.
 566                         String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 567
 568                         // Get an input stream for the file name.
 569                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 570
 571                         // Get the salt from the beginning of the import file.
 572                         byte[] saltByteArray = new byte[32];
 573                         //noinspection ResultOfMethodCallIgnored
 574                         inputStream.read(saltByteArray);
 575
 576                         // Get the initialization vector from the import file.
 577                         byte[] initializationVector = new byte[12];
 578                         //noinspection ResultOfMethodCallIgnored
 579                         inputStream.read(initializationVector);
 580
 581                         // Convert the encryption password to a byte array.
 582                         byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 583
 584                         // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 585                         byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 586                         System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 587                         System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 588
 589                         // Get a SHA-512 message digest.
 590                         MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 591
 592                         // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 593                         byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 594
 595                         // Truncate the encryption password byte array to 256 bits (32 bytes).
 596                         byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 597
 598                         // Create an AES secret key from the encryption password byte array.
 599                         SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 600
 601                         // 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.
 602                         Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 603
 604                         // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 605                         GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 606
 607                         // Initialize the cipher.
 608                         cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 609
 610                         // Create a cipher input stream.
 611                         CipherInputStream cipherInputStream = new CipherInputStream(inputStream, cipher);
 612
 613                         // 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.
 614                         int numberOfBytesRead;
 615                         byte[] decryptedBytes = new byte[16];
 616
 617
 618                         // Create a private temporary unencrypted import file.
 619                         File temporaryUnencryptedImportFile = File.createTempFile("temporary_unencrypted_import_file", null, getApplicationContext().getCacheDir());
 620
 621                         // Create an temporary unencrypted import file output stream.
 622                         FileOutputStream temporaryUnencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 623
 624
 625                         // 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.
 626                         while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 627                             // Write the data to the temporary unencrypted import file output stream.
 628                             temporaryUnencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 629                         }
 630
 631
 632                         // Flush the temporary unencrypted import file output stream.
 633                         temporaryUnencryptedImportFileOutputStream.flush();
 634
 635                         // Close the streams.
 636                         temporaryUnencryptedImportFileOutputStream.close();
 637                         cipherInputStream.close();
 638                         inputStream.close();
 639
 640                         // Wipe the encryption data from memory.
 641                         //noinspection UnusedAssignment
 642                         encryptionPasswordString = "";
 643                         Arrays.fill(saltByteArray, (byte) 0);
 644                         Arrays.fill(initializationVector, (byte) 0);
 645                         Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 646                         Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 647                         Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 648                         Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 649                         Arrays.fill(decryptedBytes, (byte) 0);
 650
 651                         // Create a temporary unencrypted import file input stream.
 652                         FileInputStream temporaryUnencryptedImportFileInputStream = new FileInputStream(temporaryUnencryptedImportFile);
 653
 654                         // Import the temporary unencrypted import file.
 655                         importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFileInputStream, this);
 656
 657                         // Close the temporary unencrypted import file input stream.
 658                         temporaryUnencryptedImportFileInputStream.close();
 659
 660                         // Delete the temporary unencrypted import file.
 661                         //noinspection ResultOfMethodCallIgnored
 662                         temporaryUnencryptedImportFile.delete();
 663
 664                         // Restart Privacy Browser if successful.
 665                         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 666                             restartPrivacyBrowser();
 667                         }
 668                     } catch (Exception exception) {
 669                         // Update the import status.
 670                         importStatus = exception.toString();
 671                     }
 672                     break;
 673
 674                 case OPENPGP_ENCRYPTION:
 675                     try {
 676                         // Set the temporary PGP encrypted import file.
 677                         temporaryPgpEncryptedImportFile = File.createTempFile("temporary_pgp_encrypted_import_file", null, getApplicationContext().getCacheDir());
 678
 679                         // Create a temporary PGP encrypted import file output stream.
 680                         FileOutputStream temporaryPgpEncryptedImportFileOutputStream = new FileOutputStream(temporaryPgpEncryptedImportFile);
 681
 682                         // Get an input stream for the file name.
 683                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 684
 685                         // Create a transfer byte array.
 686                         byte[] transferByteArray = new byte[1024];
 687
 688                         // Create an integer to track the number of bytes read.
 689                         int bytesRead;
 690
 691                         // Copy the input stream to the temporary PGP encrypted import file.
 692                         while ((bytesRead = inputStream.read(transferByteArray)) > 0) {
 693                             temporaryPgpEncryptedImportFileOutputStream.write(transferByteArray, 0, bytesRead);
 694                         }
 695
 696                         // Flush the temporary PGP encrypted import file output stream.
 697                         temporaryPgpEncryptedImportFileOutputStream.flush();
 698
 699                         // Close the streams.
 700                         inputStream.close();
 701                         temporaryPgpEncryptedImportFileOutputStream.close();
 702
 703                         // Create an decryption intent for OpenKeychain.
 704                         Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
 705
 706                         // Include the URI to be decrypted.
 707                         openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryPgpEncryptedImportFile));
 708
 709                         // Allow OpenKeychain to read the file URI.
 710                         openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 711
 712                         // Send the intent to the OpenKeychain package.
 713                         openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
 714
 715                         // Make it so.
 716                         startActivityForResult(openKeychainDecryptIntent, OPENPGP_IMPORT_RESULT_CODE);
 717
 718                         // Update the import status.
 719                         importStatus = ImportExportDatabaseHelper.IMPORT_SUCCESSFUL;
 720                     } catch (Exception exception) {
 721                         // Update the import status.
 722                         importStatus = exception.toString();
 723                     }
 724                     break;
 725             }
 726
 727             // Respond to the import status.
 728             if (!importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 729                 // Display a snack bar with the import error.
 730                 Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 731             }
 732         } else {  // Export is selected.
 733             // Export according to the encryption type.
 734             switch (encryptionSpinner.getSelectedItemPosition()) {
 735                 case NO_ENCRYPTION:
 736                     // Get the file name string.
 737                     String noEncryptionFileNameString = fileNameEditText.getText().toString();
 738
 739                     try {
 740                         // Get the export file output stream.
 741                         OutputStream exportFileOutputStream = getContentResolver().openOutputStream(Uri.parse(noEncryptionFileNameString));
 742
 743                         // Export the unencrypted file.
 744                         String noEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(exportFileOutputStream, this);
 745
 746                         // Display an export disposition snackbar.
 747                         if (noEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 748                             Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 749                         } else {
 750                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + noEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 751                         }
 752                     } catch (FileNotFoundException fileNotFoundException) {
 753                         // Display a snackbar with the exception.
 754                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + fileNotFoundException, Snackbar.LENGTH_INDEFINITE).show();
 755                     }
 756                     break;
 757
 758                 case PASSWORD_ENCRYPTION:
 759                     try {
 760                         // Create a temporary unencrypted export file.
 761                         File temporaryUnencryptedExportFile = File.createTempFile("temporary_unencrypted_export_file", null, getApplicationContext().getCacheDir());
 762
 763                         // Create a temporary unencrypted export output stream.
 764                         FileOutputStream temporaryUnencryptedExportOutputStream = new FileOutputStream(temporaryUnencryptedExportFile);
 765
 766                         // Populate the temporary unencrypted export.
 767                         String passwordEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportOutputStream, this);
 768
 769                         // Close the temporary unencrypted export output stream.
 770                         temporaryUnencryptedExportOutputStream.close();
 771
 772                         // Create an unencrypted export file input stream.
 773                         FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 774
 775                         // Get the encryption password.
 776                         String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 777
 778                         // Initialize a secure random number generator.
 779                         SecureRandom secureRandom = new SecureRandom();
 780
 781                         // Get a 256 bit (32 byte) random salt.
 782                         byte[] saltByteArray = new byte[32];
 783                         secureRandom.nextBytes(saltByteArray);
 784
 785                         // Convert the encryption password to a byte array.
 786                         byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 787
 788                         // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 789                         byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 790                         System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 791                         System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 792
 793                         // Get a SHA-512 message digest.
 794                         MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 795
 796                         // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 797                         byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 798
 799                         // Truncate the encryption password byte array to 256 bits (32 bytes).
 800                         byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 801
 802                         // Create an AES secret key from the encryption password byte array.
 803                         SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 804
 805                         // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 806                         byte[] initializationVector = new byte[12];
 807                         secureRandom.nextBytes(initializationVector);
 808
 809                         // 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.
 810                         Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 811
 812                         // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 813                         GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 814
 815                         // Initialize the cipher.
 816                         cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 817
 818                         // Get the file name string.
 819                         String passwordEncryptionFileNameString = fileNameEditText.getText().toString();
 820
 821                         // Get the export file output stream.
 822                         OutputStream exportFileOutputStream = getContentResolver().openOutputStream(Uri.parse(passwordEncryptionFileNameString));
 823
 824                         // Add the salt and the initialization vector to the export file output stream.
 825                         exportFileOutputStream.write(saltByteArray);
 826                         exportFileOutputStream.write(initializationVector);
 827
 828                         // Create a cipher output stream.
 829                         CipherOutputStream cipherOutputStream = new CipherOutputStream(exportFileOutputStream, cipher);
 830
 831                         // 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.
 832                         int numberOfBytesRead;
 833                         byte[] encryptedBytes = new byte[16];
 834
 835                         // 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.
 836                         while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 837                             // Write the data to the cipher output stream.
 838                             cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 839                         }
 840
 841                         // Close the streams.
 842                         cipherOutputStream.flush();
 843                         cipherOutputStream.close();
 844                         exportFileOutputStream.close();
 845                         unencryptedExportFileInputStream.close();
 846
 847                         // Wipe the encryption data from memory.
 848                         //noinspection UnusedAssignment
 849                         encryptionPasswordString = "";
 850                         Arrays.fill(saltByteArray, (byte) 0);
 851                         Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 852                         Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 853                         Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 854                         Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 855                         Arrays.fill(initializationVector, (byte) 0);
 856                         Arrays.fill(encryptedBytes, (byte) 0);
 857
 858                         // Delete the temporary unencrypted export file.
 859                         //noinspection ResultOfMethodCallIgnored
 860                         temporaryUnencryptedExportFile.delete();
 861
 862                         // Display an export disposition snackbar.
 863                         if (passwordEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 864                             Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 865                         } else {
 866                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + passwordEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 867                         }
 868                     } catch (Exception exception) {
 869                         // Display a snackbar with the exception.
 870                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exception, Snackbar.LENGTH_INDEFINITE).show();
 871                     }
 872                     break;
 873
 874                 case OPENPGP_ENCRYPTION:
 875                     try {
 876                         // Set the temporary pre-encrypted export file.
 877                         temporaryPreEncryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs");
 878
 879                         // Delete the temporary pre-encrypted export file if it already exists.
 880                         if (temporaryPreEncryptedExportFile.exists()) {
 881                             //noinspection ResultOfMethodCallIgnored
 882                             temporaryPreEncryptedExportFile.delete();
 883                         }
 884
 885                         // Create a temporary pre-encrypted export output stream.
 886                         FileOutputStream temporaryPreEncryptedExportOutputStream = new FileOutputStream(temporaryPreEncryptedExportFile);
 887
 888                         // Populate the temporary pre-encrypted export file.
 889                         String openpgpEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryPreEncryptedExportOutputStream, this);
 890
 891                         // Flush the temporary pre-encryption export output stream.
 892                         temporaryPreEncryptedExportOutputStream.flush();
 893
 894                         // Close the temporary pre-encryption export output stream.
 895                         temporaryPreEncryptedExportOutputStream.close();
 896
 897                         // Display an export error snackbar if the temporary pre-encrypted export failed.
 898                         if (!openpgpEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 899                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + openpgpEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 900                         }
 901
 902                         // Create an encryption intent for OpenKeychain.
 903                         Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 904
 905                         // Include the temporary unencrypted export file URI.
 906                         openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryPreEncryptedExportFile));
 907
 908                         // Allow OpenKeychain to read the file URI.
 909                         openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 910
 911                         // Send the intent to the OpenKeychain package.
 912                         openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 913
 914                         // Make it so.
 915                         startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 916                     } catch (Exception exception) {
 917                         // Display a snackbar with the exception.
 918                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exception, Snackbar.LENGTH_INDEFINITE).show();
 919                     }
 920                     break;
 921             }
 922         }
 923     }
 924
 925     private void restartPrivacyBrowser() {
 926         // Create an intent to restart Privacy Browser.
 927         Intent restartIntent = getParentActivityIntent();
 928
 929         // Assert that the intent is not null to remove the lint error below.
 930         assert restartIntent != null;
 931
 932         // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 933         restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 934
 935         // Create a restart handler.
 936         Handler restartHandler = new Handler();
 937
 938         // Create a restart runnable.
 939         Runnable restartRunnable =  () -> {
 940             // Restart Privacy Browser.
 941             startActivity(restartIntent);
 942
 943             // Kill this instance of Privacy Browser.  Otherwise, the app exhibits sporadic behavior after the restart.
 944             System.exit(0);
 945         };
 946
 947         // Restart Privacy Browser after 150 milliseconds to allow enough time for the preferences to be saved.
 948         restartHandler.postDelayed(restartRunnable, 150);
 949     }
 950 }