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

   1 /*
   2  * Copyright © 2018-2022 Soren Stoutner <soren@stoutner.com>.
   3  *
   4  * This file is part of Privacy Browser Android <https://www.stoutner.com/privacy-browser-android>.
   5  *
   6  * Privacy Browser Android 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 Android 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 Android.  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.Bundle;
  28 import android.os.Handler;
  29 import android.preference.PreferenceManager;
  30 import android.text.Editable;
  31 import android.text.TextWatcher;
  32 import android.view.View;
  33 import android.view.WindowManager;
  34 import android.widget.AdapterView;
  35 import android.widget.ArrayAdapter;
  36 import android.widget.Button;
  37 import android.widget.EditText;
  38 import android.widget.LinearLayout;
  39 import android.widget.RadioButton;
  40 import android.widget.Spinner;
  41 import android.widget.TextView;
  42
  43 import androidx.annotation.NonNull;
  44 import androidx.appcompat.app.ActionBar;
  45 import androidx.appcompat.app.AppCompatActivity;
  46 import androidx.appcompat.widget.Toolbar;
  47 import androidx.cardview.widget.CardView;
  48 import androidx.core.content.FileProvider;
  49
  50 import com.google.android.material.snackbar.Snackbar;
  51 import com.google.android.material.textfield.TextInputLayout;
  52
  53 import com.stoutner.privacybrowser.BuildConfig;
  54 import com.stoutner.privacybrowser.R;
  55 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  56
  57 import java.io.File;
  58 import java.io.FileInputStream;
  59 import java.io.FileNotFoundException;
  60 import java.io.FileOutputStream;
  61 import java.io.InputStream;
  62 import java.io.OutputStream;
  63 import java.nio.charset.StandardCharsets;
  64 import java.security.MessageDigest;
  65 import java.security.SecureRandom;
  66 import java.util.Arrays;
  67
  68 import javax.crypto.Cipher;
  69 import javax.crypto.CipherInputStream;
  70 import javax.crypto.CipherOutputStream;
  71 import javax.crypto.spec.GCMParameterSpec;
  72 import javax.crypto.spec.SecretKeySpec;
  73
  74 public class ImportExportActivity extends AppCompatActivity {
  75     // Define the encryption constants.
  76     private final int NO_ENCRYPTION = 0;
  77     private final int PASSWORD_ENCRYPTION = 1;
  78     private final int OPENPGP_ENCRYPTION = 2;
  79
  80     // Define the activity result constants.
  81     private final int BROWSE_RESULT_CODE = 0;
  82     private final int OPENPGP_IMPORT_RESULT_CODE = 1;
  83     private final int OPENPGP_EXPORT_RESULT_CODE = 2;
  84
  85     // Define the saved instance state constants.
  86     private final String ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY = "encryption_password_textinputlayout_visibility";
  87     private final String OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY = "open_keychain_required_textview_visibility";
  88     private final String FILE_LOCATION_CARD_VIEW = "file_location_card_view";
  89     private final String FILE_NAME_LINEARLAYOUT_VISIBILITY = "file_name_linearlayout_visibility";
  90     private final String OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY = "open_keychain_import_instructions_textview_visibility";
  91     private final String IMPORT_EXPORT_BUTTON_VISIBILITY = "import_export_button_visibility";
  92     private final String FILE_NAME_TEXT = "file_name_text";
  93     private final String IMPORT_EXPORT_BUTTON_TEXT = "import_export_button_text";
  94
  95     // Define the class views.
  96     Spinner encryptionSpinner;
  97     TextInputLayout encryptionPasswordTextInputLayout;
  98     EditText encryptionPasswordEditText;
  99     TextView openKeychainRequiredTextView;
 100     CardView fileLocationCardView;
 101     RadioButton importRadioButton;
 102     LinearLayout fileNameLinearLayout;
 103     EditText fileNameEditText;
 104     TextView openKeychainImportInstructionsTextView;
 105     Button importExportButton;
 106
 107     // Define the class variables.
 108     private boolean openKeychainInstalled;
 109     private File temporaryPgpEncryptedImportFile;
 110     private File temporaryPreEncryptedExportFile;
 111
 112     @Override
 113     public void onCreate(Bundle savedInstanceState) {
 114         // Get a handle for the shared preferences.
 115         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
 116
 117         // Get the preferences.
 118         boolean allowScreenshots = sharedPreferences.getBoolean(getString(R.string.allow_screenshots_key), false);
 119         boolean bottomAppBar = sharedPreferences.getBoolean(getString(R.string.bottom_app_bar_key), false);
 120
 121         // Disable screenshots if not allowed.
 122         if (!allowScreenshots) {
 123             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
 124         }
 125
 126         // Set the theme.
 127         setTheme(R.style.PrivacyBrowser);
 128
 129         // Run the default commands.
 130         super.onCreate(savedInstanceState);
 131
 132         // Set the content view.
 133         if (bottomAppBar) {
 134             setContentView(R.layout.import_export_bottom_appbar);
 135         } else {
 136             setContentView(R.layout.import_export_top_appbar);
 137         }
 138
 139         // Get a handle for the toolbar.
 140         Toolbar toolbar = findViewById(R.id.import_export_toolbar);
 141
 142         // Set the support action bar.
 143         setSupportActionBar(toolbar);
 144
 145         // Get a handle for the action bar.
 146         ActionBar actionBar = getSupportActionBar();
 147
 148         // Remove the incorrect lint warning that the action bar might be null.
 149         assert actionBar != null;
 150
 151         // Display the home arrow on the support action bar.
 152         actionBar.setDisplayHomeAsUpEnabled(true);
 153
 154         // Find out if OpenKeychain is installed.
 155         try {
 156             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 157         } catch (PackageManager.NameNotFoundException exception) {
 158             openKeychainInstalled = false;
 159         }
 160
 161         // Get handles for the views that need to be modified.
 162         encryptionSpinner = findViewById(R.id.encryption_spinner);
 163         encryptionPasswordTextInputLayout = findViewById(R.id.encryption_password_textinputlayout);
 164         encryptionPasswordEditText = findViewById(R.id.encryption_password_edittext);
 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                         openKeychainRequiredTextView.setVisibility(View.GONE);
 192                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 193
 194                         // Show the file location card.
 195                         fileLocationCardView.setVisibility(View.VISIBLE);
 196
 197                         // Show the file name linear layout if either import or export is checked.
 198                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 199                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 200                         }
 201
 202                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 203                         if (importRadioButton.isChecked()) {
 204                             importExportButton.setText(R.string.import_button);
 205                         }
 206
 207                         // Enable the import/export button if the file name is populated.
 208                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 209                         break;
 210
 211                     case PASSWORD_ENCRYPTION:
 212                         // Hide the OpenPGP layout items.
 213                         openKeychainRequiredTextView.setVisibility(View.GONE);
 214                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 215
 216                         // Show the password encryption layout items.
 217                         encryptionPasswordTextInputLayout.setVisibility(View.VISIBLE);
 218
 219                         // Show the file location card.
 220                         fileLocationCardView.setVisibility(View.VISIBLE);
 221
 222                         // Show the file name linear layout if either import or export is checked.
 223                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 224                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 225                         }
 226
 227                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 228                         if (importRadioButton.isChecked()) {
 229                             importExportButton.setText(R.string.import_button);
 230                         }
 231
 232                         // Enable the import/button if both the password and the file name are populated.
 233                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 234                         break;
 235
 236                     case OPENPGP_ENCRYPTION:
 237                         // Hide the password encryption layout items.
 238                         encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 239
 240                         // Updated items based on the installation status of OpenKeychain.
 241                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 242                             // Show the file location card.
 243                             fileLocationCardView.setVisibility(View.VISIBLE);
 244
 245                             if (importRadioButton.isChecked()) {
 246                                 // Show the file name linear layout and the OpenKeychain import instructions.
 247                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 248                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 249
 250                                 // Set the text of the import button to be `Decrypt`.
 251                                 importExportButton.setText(R.string.decrypt);
 252
 253                                 // Enable the import button if the file name is populated.
 254                                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 255                             } else if (exportRadioButton.isChecked()) {
 256                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 257                                 fileNameLinearLayout.setVisibility(View.GONE);
 258                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 259
 260                                 // Enable the export button.
 261                                 importExportButton.setEnabled(true);
 262                             }
 263                         } else {  // OpenKeychain is not installed.
 264                             // Show the OpenPGP required layout item.
 265                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 266
 267                             // Hide the file location card.
 268                             fileLocationCardView.setVisibility(View.GONE);
 269                         }
 270                         break;
 271                 }
 272             }
 273
 274             @Override
 275             public void onNothingSelected(AdapterView<?> parent) {
 276
 277             }
 278         });
 279
 280         // Update the status of the import/export button when the password changes.
 281         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 282             @Override
 283             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 284                 // Do nothing.
 285             }
 286
 287             @Override
 288             public void onTextChanged(CharSequence s, int start, int before, int count) {
 289                 // Do nothing.
 290             }
 291
 292             @Override
 293             public void afterTextChanged(Editable s) {
 294                 // Enable the import/export button if both the file string and the password are populated.
 295                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 296             }
 297         });
 298
 299         // Update the UI when the file name EditText changes.
 300         fileNameEditText.addTextChangedListener(new TextWatcher() {
 301             @Override
 302             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 303                 // Do nothing.
 304             }
 305
 306             @Override
 307             public void onTextChanged(CharSequence s, int start, int before, int count) {
 308                 // Do nothing.
 309             }
 310
 311             @Override
 312             public void afterTextChanged(Editable s) {
 313                 // Adjust the UI according to the encryption spinner position.
 314                 if (encryptionSpinner.getSelectedItemPosition() == PASSWORD_ENCRYPTION) {
 315                     // Enable the import/export button if both the file name and the password are populated.
 316                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 317                 } else {
 318                     // Enable the export button if the file name is populated.
 319                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 320                 }
 321             }
 322         });
 323
 324         // Check to see if the activity has been restarted.
 325         if (savedInstanceState == null) {  // The app has not been restarted.
 326             // Initially hide the unneeded views.
 327             encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 328             openKeychainRequiredTextView.setVisibility(View.GONE);
 329             fileNameLinearLayout.setVisibility(View.GONE);
 330             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 331             importExportButton.setVisibility(View.GONE);
 332         } else {  // The app has been restarted.
 333             // Restore the visibility of the views.
 334             encryptionPasswordTextInputLayout.setVisibility(savedInstanceState.getInt(ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY));
 335             openKeychainRequiredTextView.setVisibility(savedInstanceState.getInt(OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY));
 336             fileLocationCardView.setVisibility(savedInstanceState.getInt(FILE_LOCATION_CARD_VIEW));
 337             fileNameLinearLayout.setVisibility(savedInstanceState.getInt(FILE_NAME_LINEARLAYOUT_VISIBILITY));
 338             openKeychainImportInstructionsTextView.setVisibility(savedInstanceState.getInt(OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY));
 339             importExportButton.setVisibility(savedInstanceState.getInt(IMPORT_EXPORT_BUTTON_VISIBILITY));
 340
 341             // Restore the text.
 342             fileNameEditText.post(() -> fileNameEditText.setText(savedInstanceState.getString(FILE_NAME_TEXT)));
 343             importExportButton.setText(savedInstanceState.getString(IMPORT_EXPORT_BUTTON_TEXT));
 344         }
 345     }
 346
 347     @Override
 348     public void onSaveInstanceState (@NonNull Bundle savedInstanceState) {
 349         // Run the default commands.
 350         super.onSaveInstanceState(savedInstanceState);
 351
 352         // Save the visibility of the views.
 353         savedInstanceState.putInt(ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY, encryptionPasswordTextInputLayout.getVisibility());
 354         savedInstanceState.putInt(OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY, openKeychainRequiredTextView.getVisibility());
 355         savedInstanceState.putInt(FILE_LOCATION_CARD_VIEW, fileLocationCardView.getVisibility());
 356         savedInstanceState.putInt(FILE_NAME_LINEARLAYOUT_VISIBILITY, fileNameLinearLayout.getVisibility());
 357         savedInstanceState.putInt(OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY, openKeychainImportInstructionsTextView.getVisibility());
 358         savedInstanceState.putInt(IMPORT_EXPORT_BUTTON_VISIBILITY, importExportButton.getVisibility());
 359
 360         // Save the text.
 361         savedInstanceState.putString(FILE_NAME_TEXT, fileNameEditText.getText().toString());
 362         savedInstanceState.putString(IMPORT_EXPORT_BUTTON_TEXT, importExportButton.getText().toString());
 363     }
 364
 365     public void onClickRadioButton(View view) {
 366         // Get the current file name.
 367         String fileNameString = fileNameEditText.getText().toString();
 368
 369         // Convert the file name string to a file.
 370         File file = new File(fileNameString);
 371
 372         // Check to see if import or export was selected.
 373         if (view.getId() == R.id.import_radiobutton) {  // The import radio button is selected.
 374             // Check to see if OpenPGP encryption is selected.
 375             if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 376                 // Show the OpenKeychain import instructions.
 377                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 378
 379                 // Set the text on the import/export button to be `Decrypt`.
 380                 importExportButton.setText(R.string.decrypt);
 381             } else {  // OpenPGP encryption not selected.
 382                 // Hide the OpenKeychain import instructions.
 383                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 384
 385                 // Set the text on the import/export button to be `Import`.
 386                 importExportButton.setText(R.string.import_button);
 387             }
 388
 389             // Display the file name views.
 390             fileNameLinearLayout.setVisibility(View.VISIBLE);
 391             importExportButton.setVisibility(View.VISIBLE);
 392
 393             // Check to see if the file exists.
 394             if (file.exists()) {  // The file exists.
 395                 // Check to see if password encryption is selected.
 396                 if (encryptionSpinner.getSelectedItemPosition() == PASSWORD_ENCRYPTION) {  // Password encryption is selected.
 397                     // Enable the import button if the encryption password is populated.
 398                     importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 399                 } else {  // Password encryption is not selected.
 400                     // Enable the import/decrypt button.
 401                     importExportButton.setEnabled(true);
 402                 }
 403             } else {  // The file does not exist.
 404                 // Disable the import/decrypt button.
 405                 importExportButton.setEnabled(false);
 406             }
 407         } else {  // The export radio button is selected.
 408             // Hide the OpenKeychain import instructions.
 409             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 410
 411             // Set the text on the import/export button to be `Export`.
 412             importExportButton.setText(R.string.export);
 413
 414             // Show the import/export button.
 415             importExportButton.setVisibility(View.VISIBLE);
 416
 417             // Check to see if OpenPGP encryption is selected.
 418             if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 419                 // Hide the file name views.
 420                 fileNameLinearLayout.setVisibility(View.GONE);
 421
 422                 // Enable the export button.
 423                 importExportButton.setEnabled(true);
 424             } else {  // OpenPGP encryption is not selected.
 425                 // Show the file name view.
 426                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 427
 428                 // Check the encryption type.
 429                 if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 430                     // Enable the export button if the file name is populated.
 431                     importExportButton.setEnabled(!fileNameString.isEmpty());
 432                 } else {  // Password encryption is selected.
 433                     // Enable the export button if the file name and the password are populated.
 434                     importExportButton.setEnabled(!fileNameString.isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 435                 }
 436             }
 437         }
 438     }
 439
 440     public void browse(View view) {
 441         // Check to see if import or export is selected.
 442         if (importRadioButton.isChecked()) {  // Import is selected.
 443             // Create the file picker intent.
 444             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 445
 446             // Set the intent MIME type to include all files so that everything is visible.
 447             importBrowseIntent.setType("*/*");
 448
 449             // Request a file that can be opened.
 450             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 451
 452             // Launch the file picker.
 453             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 454         } else {  // Export is selected
 455             // Create the file picker intent.
 456             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 457
 458             // Set the intent MIME type to include all files so that everything is visible.
 459             exportBrowseIntent.setType("*/*");
 460
 461             // Set the initial export file name according to the encryption type.
 462             if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 463                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs");
 464             } else {  // Password encryption is selected.
 465                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs.aes");
 466             }
 467
 468             // Request a file that can be opened.
 469             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 470
 471             // Launch the file picker.
 472             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 473         }
 474     }
 475
 476     @Override
 477     public void onActivityResult(int requestCode, int resultCode, Intent returnedIntent) {
 478         // Run the default commands.
 479         super.onActivityResult(requestCode, resultCode, returnedIntent);
 480
 481         switch (requestCode) {
 482             case (BROWSE_RESULT_CODE):
 483                 // Only do something if the user didn't press back from the file picker.
 484                 if (resultCode == Activity.RESULT_OK) {
 485                     // Get the file path URI from the intent.
 486                     Uri fileNameUri = returnedIntent.getData();
 487
 488                     // Get the file name string from the URI.
 489                     String fileNameString = fileNameUri.toString();
 490
 491                     // Set the file name name text.
 492                     fileNameEditText.setText(fileNameString);
 493
 494                     // Move the cursor to the end of the file name edit text.
 495                     fileNameEditText.setSelection(fileNameString.length());
 496                 }
 497                 break;
 498
 499             case OPENPGP_IMPORT_RESULT_CODE:
 500                 // Delete the temporary PGP encrypted import file.
 501                 if (temporaryPgpEncryptedImportFile.exists()) {
 502                     //noinspection ResultOfMethodCallIgnored
 503                     temporaryPgpEncryptedImportFile.delete();
 504                 }
 505                 break;
 506
 507             case OPENPGP_EXPORT_RESULT_CODE:
 508                 // Delete the temporary pre-encrypted export file if it exists.
 509                 if (temporaryPreEncryptedExportFile.exists()) {
 510                     //noinspection ResultOfMethodCallIgnored
 511                     temporaryPreEncryptedExportFile.delete();
 512                 }
 513                 break;
 514         }
 515     }
 516
 517     public void importExport(View view) {
 518         // Instantiate the import export database helper.
 519         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 520
 521         // Check to see if import or export is selected.
 522         if (importRadioButton.isChecked()) {  // Import is selected.
 523             // Initialize the import status string
 524             String importStatus = "";
 525
 526             // Get the file name string.
 527             String fileNameString = fileNameEditText.getText().toString();
 528
 529             // Import according to the encryption type.
 530             switch (encryptionSpinner.getSelectedItemPosition()) {
 531                 case NO_ENCRYPTION:
 532                     try {
 533                         // Get an input stream for the file name.
 534                         // A file may be opened directly once the minimum API >= 29.  <https://developer.android.com/reference/kotlin/android/content/ContentResolver#openfile>
 535                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 536
 537                         // Import the unencrypted file.
 538                         importStatus = importExportDatabaseHelper.importUnencrypted(inputStream, this);
 539                     } catch (FileNotFoundException exception) {
 540                         // Update the import status.
 541                         importStatus = exception.toString();
 542                     }
 543
 544                     // Restart Privacy Browser if successful.
 545                     if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 546                         restartPrivacyBrowser();
 547                     }
 548                     break;
 549
 550                 case PASSWORD_ENCRYPTION:
 551                     try {
 552                         // Get the encryption password.
 553                         String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 554
 555                         // Get an input stream for the file name.
 556                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 557
 558                         // Get the salt from the beginning of the import file.
 559                         byte[] saltByteArray = new byte[32];
 560                         //noinspection ResultOfMethodCallIgnored
 561                         inputStream.read(saltByteArray);
 562
 563                         // Get the initialization vector from the import file.
 564                         byte[] initializationVector = new byte[12];
 565                         //noinspection ResultOfMethodCallIgnored
 566                         inputStream.read(initializationVector);
 567
 568                         // Convert the encryption password to a byte array.
 569                         byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 570
 571                         // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 572                         byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 573                         System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 574                         System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 575
 576                         // Get a SHA-512 message digest.
 577                         MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 578
 579                         // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 580                         byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 581
 582                         // Truncate the encryption password byte array to 256 bits (32 bytes).
 583                         byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 584
 585                         // Create an AES secret key from the encryption password byte array.
 586                         SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 587
 588                         // 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.
 589                         Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 590
 591                         // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 592                         GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 593
 594                         // Initialize the cipher.
 595                         cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 596
 597                         // Create a cipher input stream.
 598                         CipherInputStream cipherInputStream = new CipherInputStream(inputStream, cipher);
 599
 600                         // 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.
 601                         int numberOfBytesRead;
 602                         byte[] decryptedBytes = new byte[16];
 603
 604
 605                         // Create a private temporary unencrypted import file.
 606                         File temporaryUnencryptedImportFile = File.createTempFile("temporary_unencrypted_import_file", null, getApplicationContext().getCacheDir());
 607
 608                         // Create an temporary unencrypted import file output stream.
 609                         FileOutputStream temporaryUnencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 610
 611
 612                         // 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.
 613                         while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 614                             // Write the data to the temporary unencrypted import file output stream.
 615                             temporaryUnencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 616                         }
 617
 618
 619                         // Flush the temporary unencrypted import file output stream.
 620                         temporaryUnencryptedImportFileOutputStream.flush();
 621
 622                         // Close the streams.
 623                         temporaryUnencryptedImportFileOutputStream.close();
 624                         cipherInputStream.close();
 625                         inputStream.close();
 626
 627                         // Wipe the encryption data from memory.
 628                         //noinspection UnusedAssignment
 629                         encryptionPasswordString = "";
 630                         Arrays.fill(saltByteArray, (byte) 0);
 631                         Arrays.fill(initializationVector, (byte) 0);
 632                         Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 633                         Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 634                         Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 635                         Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 636                         Arrays.fill(decryptedBytes, (byte) 0);
 637
 638                         // Create a temporary unencrypted import file input stream.
 639                         FileInputStream temporaryUnencryptedImportFileInputStream = new FileInputStream(temporaryUnencryptedImportFile);
 640
 641                         // Import the temporary unencrypted import file.
 642                         importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFileInputStream, this);
 643
 644                         // Close the temporary unencrypted import file input stream.
 645                         temporaryUnencryptedImportFileInputStream.close();
 646
 647                         // Delete the temporary unencrypted import file.
 648                         //noinspection ResultOfMethodCallIgnored
 649                         temporaryUnencryptedImportFile.delete();
 650
 651                         // Restart Privacy Browser if successful.
 652                         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 653                             restartPrivacyBrowser();
 654                         }
 655                     } catch (Exception exception) {
 656                         // Update the import status.
 657                         importStatus = exception.toString();
 658                     }
 659                     break;
 660
 661                 case OPENPGP_ENCRYPTION:
 662                     try {
 663                         // Set the temporary PGP encrypted import file.
 664                         temporaryPgpEncryptedImportFile = File.createTempFile("temporary_pgp_encrypted_import_file", null, getApplicationContext().getCacheDir());
 665
 666                         // Create a temporary PGP encrypted import file output stream.
 667                         FileOutputStream temporaryPgpEncryptedImportFileOutputStream = new FileOutputStream(temporaryPgpEncryptedImportFile);
 668
 669                         // Get an input stream for the file name.
 670                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 671
 672                         // Create a transfer byte array.
 673                         byte[] transferByteArray = new byte[1024];
 674
 675                         // Create an integer to track the number of bytes read.
 676                         int bytesRead;
 677
 678                         // Copy the input stream to the temporary PGP encrypted import file.
 679                         while ((bytesRead = inputStream.read(transferByteArray)) > 0) {
 680                             temporaryPgpEncryptedImportFileOutputStream.write(transferByteArray, 0, bytesRead);
 681                         }
 682
 683                         // Flush the temporary PGP encrypted import file output stream.
 684                         temporaryPgpEncryptedImportFileOutputStream.flush();
 685
 686                         // Close the streams.
 687                         inputStream.close();
 688                         temporaryPgpEncryptedImportFileOutputStream.close();
 689
 690                         // Create an decryption intent for OpenKeychain.
 691                         Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
 692
 693                         // Include the URI to be decrypted.
 694                         openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryPgpEncryptedImportFile));
 695
 696                         // Allow OpenKeychain to read the file URI.
 697                         openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 698
 699                         // Send the intent to the OpenKeychain package.
 700                         openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
 701
 702                         // Make it so.
 703                         startActivityForResult(openKeychainDecryptIntent, OPENPGP_IMPORT_RESULT_CODE);
 704
 705                         // Update the import status.
 706                         importStatus = ImportExportDatabaseHelper.IMPORT_SUCCESSFUL;
 707                     } catch (Exception exception) {
 708                         // Update the import status.
 709                         importStatus = exception.toString();
 710                     }
 711                     break;
 712             }
 713
 714             // Respond to the import status.
 715             if (!importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 716                 // Display a snack bar with the import error.
 717                 Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 718             }
 719         } else {  // Export is selected.
 720             // Export according to the encryption type.
 721             switch (encryptionSpinner.getSelectedItemPosition()) {
 722                 case NO_ENCRYPTION:
 723                     // Get the file name string.
 724                     String noEncryptionFileNameString = fileNameEditText.getText().toString();
 725
 726                     try {
 727                         // Get the export file output stream.
 728                         // A file may be opened directly once the minimum API >= 29.  <https://developer.android.com/reference/kotlin/android/content/ContentResolver#openfile>
 729                         OutputStream exportFileOutputStream = getContentResolver().openOutputStream(Uri.parse(noEncryptionFileNameString));
 730
 731                         // Export the unencrypted file.
 732                         String noEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(exportFileOutputStream, this);
 733
 734                         // Display an export disposition snackbar.
 735                         if (noEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 736                             Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 737                         } else {
 738                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + noEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 739                         }
 740                     } catch (FileNotFoundException fileNotFoundException) {
 741                         // Display a snackbar with the exception.
 742                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + fileNotFoundException, Snackbar.LENGTH_INDEFINITE).show();
 743                     }
 744                     break;
 745
 746                 case PASSWORD_ENCRYPTION:
 747                     try {
 748                         // Create a temporary unencrypted export file.
 749                         File temporaryUnencryptedExportFile = File.createTempFile("temporary_unencrypted_export_file", null, getApplicationContext().getCacheDir());
 750
 751                         // Create a temporary unencrypted export output stream.
 752                         FileOutputStream temporaryUnencryptedExportOutputStream = new FileOutputStream(temporaryUnencryptedExportFile);
 753
 754                         // Populate the temporary unencrypted export.
 755                         String passwordEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportOutputStream, this);
 756
 757                         // Close the temporary unencrypted export output stream.
 758                         temporaryUnencryptedExportOutputStream.close();
 759
 760                         // Create an unencrypted export file input stream.
 761                         FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 762
 763                         // Get the encryption password.
 764                         String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 765
 766                         // Initialize a secure random number generator.
 767                         SecureRandom secureRandom = new SecureRandom();
 768
 769                         // Get a 256 bit (32 byte) random salt.
 770                         byte[] saltByteArray = new byte[32];
 771                         secureRandom.nextBytes(saltByteArray);
 772
 773                         // Convert the encryption password to a byte array.
 774                         byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 775
 776                         // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 777                         byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 778                         System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 779                         System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 780
 781                         // Get a SHA-512 message digest.
 782                         MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 783
 784                         // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 785                         byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 786
 787                         // Truncate the encryption password byte array to 256 bits (32 bytes).
 788                         byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 789
 790                         // Create an AES secret key from the encryption password byte array.
 791                         SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 792
 793                         // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 794                         byte[] initializationVector = new byte[12];
 795                         secureRandom.nextBytes(initializationVector);
 796
 797                         // 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.
 798                         Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 799
 800                         // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 801                         GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 802
 803                         // Initialize the cipher.
 804                         cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 805
 806                         // Get the file name string.
 807                         String passwordEncryptionFileNameString = fileNameEditText.getText().toString();
 808
 809                         // Get the export file output stream.
 810                         OutputStream exportFileOutputStream = getContentResolver().openOutputStream(Uri.parse(passwordEncryptionFileNameString));
 811
 812                         // Add the salt and the initialization vector to the export file output stream.
 813                         exportFileOutputStream.write(saltByteArray);
 814                         exportFileOutputStream.write(initializationVector);
 815
 816                         // Create a cipher output stream.
 817                         CipherOutputStream cipherOutputStream = new CipherOutputStream(exportFileOutputStream, cipher);
 818
 819                         // 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.
 820                         int numberOfBytesRead;
 821                         byte[] encryptedBytes = new byte[16];
 822
 823                         // 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.
 824                         while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 825                             // Write the data to the cipher output stream.
 826                             cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 827                         }
 828
 829                         // Close the streams.
 830                         cipherOutputStream.flush();
 831                         cipherOutputStream.close();
 832                         exportFileOutputStream.close();
 833                         unencryptedExportFileInputStream.close();
 834
 835                         // Wipe the encryption data from memory.
 836                         //noinspection UnusedAssignment
 837                         encryptionPasswordString = "";
 838                         Arrays.fill(saltByteArray, (byte) 0);
 839                         Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 840                         Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 841                         Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 842                         Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 843                         Arrays.fill(initializationVector, (byte) 0);
 844                         Arrays.fill(encryptedBytes, (byte) 0);
 845
 846                         // Delete the temporary unencrypted export file.
 847                         //noinspection ResultOfMethodCallIgnored
 848                         temporaryUnencryptedExportFile.delete();
 849
 850                         // Display an export disposition snackbar.
 851                         if (passwordEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 852                             Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 853                         } else {
 854                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + passwordEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 855                         }
 856                     } catch (Exception exception) {
 857                         // Display a snackbar with the exception.
 858                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exception, Snackbar.LENGTH_INDEFINITE).show();
 859                     }
 860                     break;
 861
 862                 case OPENPGP_ENCRYPTION:
 863                     try {
 864                         // Set the temporary pre-encrypted export file.
 865                         temporaryPreEncryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs");
 866
 867                         // Delete the temporary pre-encrypted export file if it already exists.
 868                         if (temporaryPreEncryptedExportFile.exists()) {
 869                             //noinspection ResultOfMethodCallIgnored
 870                             temporaryPreEncryptedExportFile.delete();
 871                         }
 872
 873                         // Create a temporary pre-encrypted export output stream.
 874                         FileOutputStream temporaryPreEncryptedExportOutputStream = new FileOutputStream(temporaryPreEncryptedExportFile);
 875
 876                         // Populate the temporary pre-encrypted export file.
 877                         String openpgpEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryPreEncryptedExportOutputStream, this);
 878
 879                         // Flush the temporary pre-encryption export output stream.
 880                         temporaryPreEncryptedExportOutputStream.flush();
 881
 882                         // Close the temporary pre-encryption export output stream.
 883                         temporaryPreEncryptedExportOutputStream.close();
 884
 885                         // Display an export error snackbar if the temporary pre-encrypted export failed.
 886                         if (!openpgpEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 887                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + openpgpEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 888                         }
 889
 890                         // Create an encryption intent for OpenKeychain.
 891                         Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 892
 893                         // Include the temporary unencrypted export file URI.
 894                         openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryPreEncryptedExportFile));
 895
 896                         // Allow OpenKeychain to read the file URI.
 897                         openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 898
 899                         // Send the intent to the OpenKeychain package.
 900                         openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 901
 902                         // Make it so.
 903                         startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 904                     } catch (Exception exception) {
 905                         // Display a snackbar with the exception.
 906                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exception, Snackbar.LENGTH_INDEFINITE).show();
 907                     }
 908                     break;
 909             }
 910         }
 911     }
 912
 913     private void restartPrivacyBrowser() {
 914         // Create an intent to restart Privacy Browser.
 915         Intent restartIntent = getParentActivityIntent();
 916
 917         // Assert that the intent is not null to remove the lint error below.
 918         assert restartIntent != null;
 919
 920         // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 921         restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 922
 923         // Create a restart handler.
 924         Handler restartHandler = new Handler();
 925
 926         // Create a restart runnable.
 927         Runnable restartRunnable =  () -> {
 928             // Restart Privacy Browser.
 929             startActivity(restartIntent);
 930
 931             // Kill this instance of Privacy Browser.  Otherwise, the app exhibits sporadic behavior after the restart.
 932             System.exit(0);
 933         };
 934
 935         // Restart Privacy Browser after 150 milliseconds to allow enough time for the preferences to be saved.
 936         restartHandler.postDelayed(restartRunnable, 150);
 937     }
 938 }