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

   1 /*
   2  * Copyright © 2018-2020 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.Manifest;
  23 import android.app.Activity;
  24 import android.content.Intent;
  25 import android.content.SharedPreferences;
  26 import android.content.pm.PackageManager;
  27 import android.media.MediaScannerConnection;
  28 import android.net.Uri;
  29 import android.os.Build;
  30 import android.os.Bundle;
  31 import android.os.Environment;
  32 import android.os.Handler;
  33 import android.preference.PreferenceManager;
  34 import android.provider.DocumentsContract;
  35 import android.text.Editable;
  36 import android.text.TextWatcher;
  37 import android.view.View;
  38 import android.view.WindowManager;
  39 import android.widget.AdapterView;
  40 import android.widget.ArrayAdapter;
  41 import android.widget.Button;
  42 import android.widget.EditText;
  43 import android.widget.LinearLayout;
  44 import android.widget.RadioButton;
  45 import android.widget.Spinner;
  46 import android.widget.TextView;
  47
  48 import androidx.annotation.NonNull;
  49 import androidx.appcompat.app.ActionBar;
  50 import androidx.appcompat.app.AppCompatActivity;
  51 import androidx.appcompat.widget.Toolbar;
  52 import androidx.cardview.widget.CardView;
  53 import androidx.core.app.ActivityCompat;
  54 import androidx.core.content.ContextCompat;
  55 import androidx.core.content.FileProvider;
  56 import androidx.fragment.app.DialogFragment;
  57
  58 import com.google.android.material.snackbar.Snackbar;
  59 import com.google.android.material.textfield.TextInputLayout;
  60
  61 import com.stoutner.privacybrowser.R;
  62 import com.stoutner.privacybrowser.dialogs.StoragePermissionDialog;
  63 import com.stoutner.privacybrowser.helpers.DownloadLocationHelper;
  64 import com.stoutner.privacybrowser.helpers.FileNameHelper;
  65 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  66
  67 import java.io.File;
  68 import java.io.FileInputStream;
  69 import java.io.FileOutputStream;
  70 import java.nio.charset.StandardCharsets;
  71 import java.security.MessageDigest;
  72 import java.security.SecureRandom;
  73 import java.util.Arrays;
  74
  75 import javax.crypto.Cipher;
  76 import javax.crypto.CipherInputStream;
  77 import javax.crypto.CipherOutputStream;
  78 import javax.crypto.spec.GCMParameterSpec;
  79 import javax.crypto.spec.SecretKeySpec;
  80
  81 public class ImportExportActivity extends AppCompatActivity implements StoragePermissionDialog.StoragePermissionDialogListener {
  82     // Create the encryption constants.
  83     private final int NO_ENCRYPTION = 0;
  84     private final int PASSWORD_ENCRYPTION = 1;
  85     private final int OPENPGP_ENCRYPTION = 2;
  86
  87     // Create the activity result constants.
  88     private final int BROWSE_RESULT_CODE = 0;
  89     private final int OPENPGP_EXPORT_RESULT_CODE = 1;
  90
  91     // `openKeychainInstalled` is accessed from an inner class.
  92     private boolean openKeychainInstalled;
  93
  94     @Override
  95     public void onCreate(Bundle savedInstanceState) {
  96         // Get a handle for the shared preferences.
  97         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
  98
  99         // Get the theme and screenshot preferences.
 100         boolean darkTheme = sharedPreferences.getBoolean("dark_theme", false);
 101         boolean allowScreenshots = sharedPreferences.getBoolean("allow_screenshots", false);
 102
 103         // Disable screenshots if not allowed.
 104         if (!allowScreenshots) {
 105             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
 106         }
 107
 108         // Set the activity theme.
 109         if (darkTheme) {
 110             setTheme(R.style.PrivacyBrowserDark_SecondaryActivity);
 111         } else {
 112             setTheme(R.style.PrivacyBrowserLight_SecondaryActivity);
 113         }
 114
 115         // Run the default commands.
 116         super.onCreate(savedInstanceState);
 117
 118         // Set the content view.
 119         setContentView(R.layout.import_export_coordinatorlayout);
 120
 121         // Set the support action bar.
 122         Toolbar toolbar = findViewById(R.id.import_export_toolbar);
 123         setSupportActionBar(toolbar);
 124
 125         // Get a handle for the action bar.
 126         ActionBar actionBar = getSupportActionBar();
 127
 128         // Remove the incorrect lint warning that the action bar might be null.
 129         assert actionBar != null;
 130
 131         // Display the home arrow on the support action bar.
 132         actionBar.setDisplayHomeAsUpEnabled(true);
 133
 134         // Find out if the system is running KitKat
 135         boolean runningKitKat = (Build.VERSION.SDK_INT == 19);
 136
 137         // Find out if OpenKeychain is installed.
 138         try {
 139             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 140         } catch (PackageManager.NameNotFoundException exception) {
 141             openKeychainInstalled = false;
 142         }
 143
 144         // Get handles for the views that need to be modified.
 145         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 146         TextInputLayout passwordEncryptionTextInputLayout = findViewById(R.id.password_encryption_textinputlayout);
 147         EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 148         TextView kitKatPasswordEncryptionTextView = findViewById(R.id.kitkat_password_encryption_textview);
 149         TextView openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
 150         CardView fileLocationCardView = findViewById(R.id.file_location_cardview);
 151         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 152         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 153         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 154         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 155         TextView fileDoesNotExistTextView = findViewById(R.id.file_does_not_exist_textview);
 156         TextView fileExistsWarningTextView = findViewById(R.id.file_exists_warning_textview);
 157         TextView openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 158         Button importExportButton = findViewById(R.id.import_export_button);
 159         TextView storagePermissionTextView = findViewById(R.id.import_export_storage_permission_textview);
 160
 161         // Create an array adapter for the spinner.
 162         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 163
 164         // Set the drop down view resource on the spinner.
 165         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 166
 167         // Set the array adapter for the spinner.
 168         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 169
 170         // Initially hide the unneeded views.
 171         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 172         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 173         openKeychainRequiredTextView.setVisibility(View.GONE);
 174         fileNameLinearLayout.setVisibility(View.GONE);
 175         fileDoesNotExistTextView.setVisibility(View.GONE);
 176         fileExistsWarningTextView.setVisibility(View.GONE);
 177         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 178         importExportButton.setVisibility(View.GONE);
 179
 180         // Instantiate the download location helper.
 181         DownloadLocationHelper downloadLocationHelper = new DownloadLocationHelper();
 182
 183         // Get the default file path.
 184         String defaultFilePath = downloadLocationHelper.getDownloadLocation(this) + "/" + getString(R.string.settings_pbs);
 185
 186         // Set the other default file paths.
 187         String defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 188         String defaultPgpFilePath = defaultFilePath + ".pgp";
 189
 190         // Set the default file path.
 191         fileNameEditText.setText(defaultFilePath);
 192
 193         // Hide the storage permission text view if the permission has already been granted.
 194         if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
 195             storagePermissionTextView.setVisibility(View.GONE);
 196         }
 197
 198         // Update the UI when the spinner changes.
 199         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 200             @Override
 201             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 202                 switch (position) {
 203                     case NO_ENCRYPTION:
 204                         // Hide the unneeded layout items.
 205                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 206                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 207                         openKeychainRequiredTextView.setVisibility(View.GONE);
 208                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 209
 210                         // Show the file location card.
 211                         fileLocationCardView.setVisibility(View.VISIBLE);
 212
 213                         // Show the file name linear layout if either import or export is checked.
 214                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 215                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 216                         }
 217
 218                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 219                         if (importRadioButton.isChecked()) {
 220                             importExportButton.setText(R.string.import_button);
 221                         }
 222
 223                         // Reset the default file path.
 224                         fileNameEditText.setText(defaultFilePath);
 225                         break;
 226
 227                     case PASSWORD_ENCRYPTION:
 228                         if (runningKitKat) {
 229                             // Show the KitKat password encryption message.
 230                             kitKatPasswordEncryptionTextView.setVisibility(View.VISIBLE);
 231
 232                             // Hide the OpenPGP required text view and the file location card.
 233                             openKeychainRequiredTextView.setVisibility(View.GONE);
 234                             fileLocationCardView.setVisibility(View.GONE);
 235                         } else {
 236                             // Hide the OpenPGP layout items.
 237                             openKeychainRequiredTextView.setVisibility(View.GONE);
 238                             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 239
 240                             // Show the password encryption layout items.
 241                             passwordEncryptionTextInputLayout.setVisibility(View.VISIBLE);
 242
 243                             // Show the file location card.
 244                             fileLocationCardView.setVisibility(View.VISIBLE);
 245
 246                             // Show the file name linear layout if either import or export is checked.
 247                             if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 248                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 249                             }
 250
 251                             // Reset the text of the import button, which may have been changed to `Decrypt`.
 252                             if (importRadioButton.isChecked()) {
 253                                 importExportButton.setText(R.string.import_button);
 254                             }
 255
 256                             // Update the default file path.
 257                             fileNameEditText.setText(defaultPasswordEncryptionFilePath);
 258                         }
 259                         break;
 260
 261                     case OPENPGP_ENCRYPTION:
 262                         // Hide the password encryption layout items.
 263                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 264                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 265
 266                         // Updated items based on the installation status of OpenKeychain.
 267                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 268                             // Update the default file path.
 269                             fileNameEditText.setText(defaultPgpFilePath);
 270
 271                             // Show the file location card.
 272                             fileLocationCardView.setVisibility(View.VISIBLE);
 273
 274                             if (importRadioButton.isChecked()) {
 275                                 // Show the file name linear layout and the OpenKeychain import instructions.
 276                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 277                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 278
 279                                 // Set the text of the import button to be `Decrypt`.
 280                                 importExportButton.setText(R.string.decrypt);
 281                             } else if (exportRadioButton.isChecked()) {
 282                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 283                                 fileNameLinearLayout.setVisibility(View.GONE);
 284                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 285                             }
 286                         } else {  // OpenKeychain is not installed.
 287                             // Show the OpenPGP required layout item.
 288                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 289
 290                             // Hide the file location card.
 291                             fileLocationCardView.setVisibility(View.GONE);
 292                         }
 293                         break;
 294                 }
 295             }
 296
 297             @Override
 298             public void onNothingSelected(AdapterView<?> parent) {
 299
 300             }
 301         });
 302
 303         // Update the status of the import/export button when the password changes.
 304         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 305             @Override
 306             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 307                 // Do nothing.
 308             }
 309
 310             @Override
 311             public void onTextChanged(CharSequence s, int start, int before, int count) {
 312                 // Do nothing.
 313             }
 314
 315             @Override
 316             public void afterTextChanged(Editable s) {
 317                 // Get the current file name.
 318                 String fileNameString = fileNameEditText.getText().toString();
 319
 320                 // Convert the file name string to a file.
 321                 File file = new File(fileNameString);
 322
 323                 // Update the import/export button.
 324                 if (importRadioButton.isChecked()) {  // The import radio button is checked.
 325                     // Enable the import button if the file and the password exists.
 326                     importExportButton.setEnabled(file.exists() && !encryptionPasswordEditText.getText().toString().isEmpty());
 327                 } else if (exportRadioButton.isChecked()) {  // The export radio button is checked.
 328                     // Enable the export button if the file string and the password exists.
 329                     importExportButton.setEnabled(!fileNameString.isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 330                 }
 331             }
 332         });
 333
 334         // Update the UI when the file name EditText changes.
 335         fileNameEditText.addTextChangedListener(new TextWatcher() {
 336             @Override
 337             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 338                 // Do nothing.
 339             }
 340
 341             @Override
 342             public void onTextChanged(CharSequence s, int start, int before, int count) {
 343                 // Do nothing.
 344             }
 345
 346             @Override
 347             public void afterTextChanged(Editable s) {
 348                 // Get the current file name.
 349                 String fileNameString = fileNameEditText.getText().toString();
 350
 351                 // Convert the file name string to a file.
 352                 File file = new File(fileNameString);
 353
 354                 // Adjust the UI according to the encryption spinner position.
 355                 switch (encryptionSpinner.getSelectedItemPosition()) {
 356                     case NO_ENCRYPTION:
 357                         // Determine if import or export is checked.
 358                         if (exportRadioButton.isChecked()) {  // The export radio button is checked.
 359                             // Hide the file does not exist text view.
 360                             fileDoesNotExistTextView.setVisibility(View.GONE);
 361
 362                             // Display a warning if the file already exists.
 363                             if (file.exists()) {
 364                                 fileExistsWarningTextView.setVisibility(View.VISIBLE);
 365                             } else {
 366                                 fileExistsWarningTextView.setVisibility(View.GONE);
 367                             }
 368
 369                             // Enable the export button if the file name is populated.
 370                             importExportButton.setEnabled(!fileNameString.isEmpty());
 371                         } else if (importRadioButton.isChecked()) {  // The import radio button is checked.
 372                             // Hide the file exists warning text view.
 373                             fileExistsWarningTextView.setVisibility(View.GONE);
 374
 375                             // Check if the file exists.
 376                             if (file.exists()) {  // The file exists.
 377                                 // Hide the notification that the file does not exist.
 378                                 fileDoesNotExistTextView.setVisibility(View.GONE);
 379
 380                                 // Enable the import button.
 381                                 importExportButton.setEnabled(true);
 382                             } else {  // The file does not exist.
 383                                 // Show a notification that the file does not exist.
 384                                 fileDoesNotExistTextView.setVisibility(View.VISIBLE);
 385
 386                                 // Disable the import button.
 387                                 importExportButton.setEnabled(false);
 388                             }
 389                         } else {  // Neither radio button is checked.
 390                             // Hide the file notification text views.
 391                             fileExistsWarningTextView.setVisibility(View.GONE);
 392                             fileDoesNotExistTextView.setVisibility(View.GONE);
 393                         }
 394                         break;
 395
 396                     case PASSWORD_ENCRYPTION:
 397                         // Determine if import or export is checked.
 398                         if (exportRadioButton.isChecked()) {  // The export radio button is checked.
 399                             // Hide the notification that the file does not exist.
 400                             fileDoesNotExistTextView.setVisibility(View.GONE);
 401
 402                             // Display a warning if the file already exists.
 403                             if (file.exists()) {
 404                                 fileExistsWarningTextView.setVisibility(View.VISIBLE);
 405                             } else {
 406                                 fileExistsWarningTextView.setVisibility(View.GONE);
 407                             }
 408
 409                             // Enable the export button if the file name and the password are populated.
 410                             importExportButton.setEnabled(!fileNameString.isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 411                         } else if (importRadioButton.isChecked()) {  // The import radio button is checked.
 412                             // Hide the file exists warning text view.
 413                             fileExistsWarningTextView.setVisibility(View.GONE);
 414
 415                             // Check if the file exists.
 416                             if (file.exists()) {  // The file exists.
 417                                 // Hide the notification that the file does not exist.
 418                                 fileDoesNotExistTextView.setVisibility(View.GONE);
 419
 420                                 // Enable the import button if the password is populated.
 421                                 importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 422                             } else {  // The file does not exist.
 423                                 // Show a notification that the file does not exist.
 424                                 fileDoesNotExistTextView.setVisibility(View.VISIBLE);
 425
 426                                 // Disable the import button.
 427                                 importExportButton.setEnabled(false);
 428                             }
 429                         } else {  // Neither radio button is checked.
 430                             // Hide the file notification text views.
 431                             fileExistsWarningTextView.setVisibility(View.GONE);
 432                             fileDoesNotExistTextView.setVisibility(View.GONE);
 433                         }
 434                         break;
 435
 436                     case OPENPGP_ENCRYPTION:
 437                         // Hide the file exists warning text view.
 438                         fileExistsWarningTextView.setVisibility(View.GONE);
 439
 440                         if (importRadioButton.isChecked()) {  // The import radio button is checked.
 441                             if (file.exists()) {  // The file exists.
 442                                 // Hide the notification that the file does not exist.
 443                                 fileDoesNotExistTextView.setVisibility(View.GONE);
 444
 445                                 // Enable the import button if OpenKeychain is installed.
 446                                 importExportButton.setEnabled(openKeychainInstalled);
 447                             } else {  // The file does not exist.
 448                                 // Show the notification that the file does not exist.
 449                                 fileDoesNotExistTextView.setVisibility(View.VISIBLE);
 450
 451                                 // Disable the import button.
 452                                 importExportButton.setEnabled(false);
 453                             }
 454                         } else if (exportRadioButton.isChecked()){  // The export radio button is checked.
 455                             // Hide the notification that the file does not exist.
 456                             fileDoesNotExistTextView.setVisibility(View.GONE);
 457
 458                             // Enable the export button.
 459                             importExportButton.setEnabled(true);
 460                         } else {  // Neither radio button is checked.
 461                             // Hide the notification that the file does not exist.
 462                             fileDoesNotExistTextView.setVisibility(View.GONE);
 463                         }
 464                         break;
 465                 }
 466             }
 467         });
 468     }
 469
 470     public void onClickRadioButton(View view) {
 471         // Get handles for the views.
 472         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 473         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 474         EditText passwordEncryptionEditText = findViewById(R.id.password_encryption_edittext);
 475         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 476         TextView fileDoesNotExistTextView = findViewById(R.id.file_does_not_exist_textview);
 477         TextView fileExistsWarningTextView = findViewById(R.id.file_exists_warning_textview);
 478         TextView openKeychainImportInstructionTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 479         Button importExportButton = findViewById(R.id.import_export_button);
 480
 481         // Get the current file name.
 482         String fileNameString = fileNameEditText.getText().toString();
 483
 484         // Convert the file name string to a file.
 485         File file = new File(fileNameString);
 486
 487         // Check to see if import or export was selected.
 488         switch (view.getId()) {
 489             case R.id.import_radiobutton:
 490                 // Check to see if OpenPGP encryption is selected.
 491                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 492                     // Show the OpenKeychain import instructions.
 493                     openKeychainImportInstructionTextView.setVisibility(View.VISIBLE);
 494
 495                     // Set the text on the import/export button to be `Decrypt`.
 496                     importExportButton.setText(R.string.decrypt);
 497                 } else {  // OpenPGP encryption not selected.
 498                     // Hide the OpenKeychain import instructions.
 499                     openKeychainImportInstructionTextView.setVisibility(View.GONE);
 500
 501                     // Set the text on the import/export button to be `Import`.
 502                     importExportButton.setText(R.string.import_button);
 503                 }
 504
 505                 // Hide the file exists warning text view.
 506                 fileExistsWarningTextView.setVisibility(View.GONE);
 507
 508                 // Display the file name views.
 509                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 510                 importExportButton.setVisibility(View.VISIBLE);
 511
 512                 // Check to see if the file exists.
 513                 if (file.exists()) {  // The file exists.
 514                     // Hide the notification that the file does not exist.
 515                     fileDoesNotExistTextView.setVisibility(View.GONE);
 516
 517                     // Check to see if password encryption is selected.
 518                     if (encryptionSpinner.getSelectedItemPosition() == PASSWORD_ENCRYPTION) {  // Password encryption is selected.
 519                         // Enable the import button if the encryption password is populated.
 520                         importExportButton.setEnabled(!passwordEncryptionEditText.getText().toString().isEmpty());
 521                     } else {  // Password encryption is not selected.
 522                         // Enable the import/decrypt button.
 523                         importExportButton.setEnabled(true);
 524                     }
 525                 } else {  // The file does not exist.
 526                     // Show the notification that the file does not exist.
 527                     fileDoesNotExistTextView.setVisibility(View.VISIBLE);
 528
 529                     // Disable the import/decrypt button.
 530                     importExportButton.setEnabled(false);
 531                 }
 532                 break;
 533
 534             case R.id.export_radiobutton:
 535                 // Hide the OpenKeychain import instructions.
 536                 openKeychainImportInstructionTextView.setVisibility(View.GONE);
 537
 538                 // Set the text on the import/export button to be `Export`.
 539                 importExportButton.setText(R.string.export);
 540
 541                 // Show the import/export button.
 542                 importExportButton.setVisibility(View.VISIBLE);
 543
 544                 // Check to see if OpenPGP encryption is selected.
 545                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 546                     // Hide the file name views.
 547                     fileNameLinearLayout.setVisibility(View.GONE);
 548                     fileDoesNotExistTextView.setVisibility(View.GONE);
 549                     fileExistsWarningTextView.setVisibility(View.GONE);
 550
 551                     // Enable the export button.
 552                     importExportButton.setEnabled(true);
 553                 } else {  // OpenPGP encryption is not selected.
 554                     // Show the file name view.
 555                     fileNameLinearLayout.setVisibility(View.VISIBLE);
 556
 557                     // Hide the notification that the file name does not exist.
 558                     fileDoesNotExistTextView.setVisibility(View.GONE);
 559
 560                     // Display a warning if the file already exists.
 561                     if (file.exists()) {
 562                         fileExistsWarningTextView.setVisibility(View.VISIBLE);
 563                     } else {
 564                         fileExistsWarningTextView.setVisibility(View.GONE);
 565                     }
 566
 567                     // Check the encryption type.
 568                     if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 569                         // Enable the export button if the file name is populated.
 570                         importExportButton.setEnabled(!fileNameString.isEmpty());
 571                     } else {  // Password encryption is selected.
 572                         // Enable the export button if the file name and the password are populated.
 573                         importExportButton.setEnabled(!fileNameString.isEmpty() && !passwordEncryptionEditText.getText().toString().isEmpty());
 574                     }
 575                 }
 576                 break;
 577         }
 578     }
 579
 580     public void browse(View view) {
 581         // Get a handle for the views.
 582         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 583         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 584
 585         // Check to see if import or export is selected.
 586         if (importRadioButton.isChecked()) {  // Import is selected.
 587             // Create the file picker intent.
 588             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 589
 590             // Set the intent MIME type to include all files so that everything is visible.
 591             importBrowseIntent.setType("*/*");
 592
 593             // Set the initial directory if the minimum API >= 26.
 594             if (Build.VERSION.SDK_INT >= 26) {
 595                 importBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 596             }
 597
 598             // Request a file that can be opened.
 599             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 600
 601             // Launch the file picker.
 602             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 603         } else {  // Export is selected
 604             // Create the file picker intent.
 605             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 606
 607             // Set the intent MIME type to include all files so that everything is visible.
 608             exportBrowseIntent.setType("*/*");
 609
 610             // Set the initial export file name according to the encryption type.
 611             if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 612                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings_pbs));
 613             } else {  // Password encryption is selected.
 614                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings_pbs) + ".aes");
 615             }
 616
 617             // Set the initial directory if the minimum API >= 26.
 618             if (Build.VERSION.SDK_INT >= 26) {
 619                 exportBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 620             }
 621
 622             // Request a file that can be opened.
 623             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 624
 625             // Launch the file picker.
 626             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 627         }
 628     }
 629
 630     public void importExport(View view) {
 631         // Get a handle for the views.
 632         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 633         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 634         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 635
 636         // Check to see if the storage permission is needed.
 637         if ((encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) && exportRadioButton.isChecked()) {  // Permission not needed to export via OpenKeychain.
 638             // Export the settings.
 639             exportSettings();
 640         } else if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 641             // Check to see if import or export is selected.
 642             if (importRadioButton.isChecked()) {  // Import is selected.
 643                 // Import the settings.
 644                 importSettings();
 645             } else {  // Export is selected.
 646                 // Export the settings.
 647                 exportSettings();
 648             }
 649         } else {  // The storage permission has not been granted.
 650             // Get a handle for the file name EditText.
 651             EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 652
 653             // Get the file name string.
 654             String fileNameString = fileNameEditText.getText().toString();
 655
 656             // Get the external private directory `File`.
 657             File externalPrivateDirectoryFile = getExternalFilesDir(null);
 658
 659             // Remove the incorrect lint error below that the file might be null.
 660             assert externalPrivateDirectoryFile != null;
 661
 662             // Get the external private directory string.
 663             String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
 664
 665             // Check to see if the file path is in the external private directory.
 666             if (fileNameString.startsWith(externalPrivateDirectory)) {  // The file path is in the external private directory.
 667                 // Check to see if import or export is selected.
 668                 if (importRadioButton.isChecked()) {  // Import is selected.
 669                     // Import the settings.
 670                     importSettings();
 671                 } else {  // Export is selected.
 672                     // Export the settings.
 673                     exportSettings();
 674                 }
 675             } else {  // The file path is in a public directory.
 676                 // Check if the user has previously denied the storage permission.
 677                 if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
 678                     // Instantiate the storage permission alert dialog.
 679                     DialogFragment storagePermissionDialogFragment = StoragePermissionDialog.displayDialog(0);
 680
 681                     // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
 682                     storagePermissionDialogFragment.show(getSupportFragmentManager(), getString(R.string.storage_permission));
 683                 } else {  // Show the permission request directly.
 684                     // Request the storage permission.  The export will be run when it finishes.
 685                     ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 686                 }
 687             }
 688         }
 689     }
 690
 691     @Override
 692     public void onCloseStoragePermissionDialog(int type) {
 693         // Request the write external storage permission.  The import/export will be run when it finishes.
 694         ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 695     }
 696
 697     @Override
 698     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
 699         // Get a handle for the import radiobutton.
 700         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 701
 702         // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 703         if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 704             // Run the import or export methods according to which radio button is selected.
 705             if (importRadioButton.isChecked()) {  // Import is selected.
 706                 // Import the settings.
 707                 importSettings();
 708             } else {  // Export is selected.
 709                 // Export the settings.
 710                 exportSettings();
 711             }
 712         } else {  // The storage permission was not granted.
 713             // Display an error snackbar.
 714             Snackbar.make(importRadioButton, getString(R.string.cannot_use_location), Snackbar.LENGTH_LONG).show();
 715         }
 716     }
 717
 718     @Override
 719     public void onActivityResult(int requestCode, int resultCode, Intent intent) {
 720         // Run the default commands.
 721         super.onActivityResult(requestCode, resultCode, intent);
 722
 723         switch (requestCode) {
 724             case (BROWSE_RESULT_CODE):
 725                 // Don't do anything if the user pressed back from the file picker.
 726                 if (resultCode == Activity.RESULT_OK) {
 727                     // Get a handle for the views.
 728                     EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 729                     TextView fileExistsWarningTextView = findViewById(R.id.file_exists_warning_textview);
 730
 731                     // Instantiate the file name helper.
 732                     FileNameHelper fileNameHelper = new FileNameHelper();
 733
 734                     // Get the file path URI from the intent.
 735                     Uri filePathUri = intent.getData();
 736
 737                     // Use the file path from the intent if it exists.
 738                     if (filePathUri != null) {
 739                         // Convert the file name URI to a file name path.
 740                         String fileNamePath = fileNameHelper.convertUriToFileNamePath(filePathUri);
 741
 742                         // Set the file name path as the text of the file name edit text.
 743                         fileNameEditText.setText(fileNamePath);
 744
 745                         // Hide the file exists warning text view, because the file picker will have just created a file if export was selected.
 746                         fileExistsWarningTextView.setVisibility(View.GONE);
 747                     }
 748                 }
 749                 break;
 750
 751             case OPENPGP_EXPORT_RESULT_CODE:
 752                 // Get the temporary unencrypted export file.
 753                 File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 754
 755                 // Delete the temporary unencrypted export file if it exists.
 756                 if (temporaryUnencryptedExportFile.exists()) {
 757                     //noinspection ResultOfMethodCallIgnored
 758                     temporaryUnencryptedExportFile.delete();
 759                 }
 760                 break;
 761         }
 762     }
 763
 764     private void exportSettings() {
 765         // Get a handle for the views.
 766         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 767         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 768
 769         // Instantiate the import export database helper.
 770         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 771
 772         // Get the export file string.
 773         String exportFileString = fileNameEditText.getText().toString();
 774
 775         // Get the export and temporary unencrypted export files.
 776         File exportFile = new File(exportFileString);
 777         File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 778
 779         // Create an export status string.
 780         String exportStatus;
 781
 782         // Export according to the encryption type.
 783         switch (encryptionSpinner.getSelectedItemPosition()) {
 784             case NO_ENCRYPTION:
 785                 // Export the unencrypted file.
 786                 exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, this);
 787
 788                 // Show a disposition snackbar.
 789                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 790                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 791                 } else {
 792                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 793                 }
 794                 break;
 795
 796             case PASSWORD_ENCRYPTION:
 797                 // Create an unencrypted export in a private directory.
 798                 exportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 799
 800                 try {
 801                     // Create an unencrypted export file input stream.
 802                     FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 803
 804                     // Delete the encrypted export file if it exists.
 805                     if (exportFile.exists()) {
 806                         //noinspection ResultOfMethodCallIgnored
 807                         exportFile.delete();
 808                     }
 809
 810                     // Create an encrypted export file output stream.
 811                     FileOutputStream encryptedExportFileOutputStream = new FileOutputStream(exportFile);
 812
 813                     // Get a handle for the encryption password EditText.
 814                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 815
 816                     // Get the encryption password.
 817                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 818
 819                     // Initialize a secure random number generator.
 820                     SecureRandom secureRandom = new SecureRandom();
 821
 822                     // Get a 256 bit (32 byte) random salt.
 823                     byte[] saltByteArray = new byte[32];
 824                     secureRandom.nextBytes(saltByteArray);
 825
 826                     // Convert the encryption password to a byte array.
 827                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 828
 829                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 830                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 831                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 832                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 833
 834                     // Get a SHA-512 message digest.
 835                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 836
 837                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 838                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 839
 840                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 841                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 842
 843                     // Create an AES secret key from the encryption password byte array.
 844                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 845
 846                     // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 847                     byte[] initializationVector = new byte[12];
 848                     secureRandom.nextBytes(initializationVector);
 849
 850                     // 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.
 851                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 852
 853                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 854                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 855
 856                     // Initialize the cipher.
 857                     cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 858
 859                     // Add the salt and the initialization vector to the export file.
 860                     encryptedExportFileOutputStream.write(saltByteArray);
 861                     encryptedExportFileOutputStream.write(initializationVector);
 862
 863                     // Create a cipher output stream.
 864                     CipherOutputStream cipherOutputStream = new CipherOutputStream(encryptedExportFileOutputStream, cipher);
 865
 866                     // 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.
 867                     int numberOfBytesRead;
 868                     byte[] encryptedBytes = new byte[16];
 869
 870                     // 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.
 871                     while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 872                         // Write the data to the cipher output stream.
 873                         cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 874                     }
 875
 876                     // Close the streams.
 877                     cipherOutputStream.flush();
 878                     cipherOutputStream.close();
 879                     encryptedExportFileOutputStream.close();
 880                     unencryptedExportFileInputStream.close();
 881
 882                     // Wipe the encryption data from memory.
 883                     //noinspection UnusedAssignment
 884                     encryptionPasswordString = "";
 885                     Arrays.fill(saltByteArray, (byte) 0);
 886                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 887                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 888                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 889                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 890                     Arrays.fill(initializationVector, (byte) 0);
 891                     Arrays.fill(encryptedBytes, (byte) 0);
 892
 893                     // Delete the temporary unencrypted export file.
 894                     //noinspection ResultOfMethodCallIgnored
 895                     temporaryUnencryptedExportFile.delete();
 896                 } catch (Exception exception) {
 897                     exportStatus = exception.toString();
 898                 }
 899
 900                 // Show a disposition snackbar.
 901                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 902                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 903                 } else {
 904                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 905                 }
 906                 break;
 907
 908             case OPENPGP_ENCRYPTION:
 909                 // Create an unencrypted export in the private location.
 910                 importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 911
 912                 // Create an encryption intent for OpenKeychain.
 913                 Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 914
 915                 // Include the temporary unencrypted export file URI.
 916                 openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryUnencryptedExportFile));
 917
 918                 // Allow OpenKeychain to read the file URI.
 919                 openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 920
 921                 // Send the intent to the OpenKeychain package.
 922                 openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 923
 924                 // Make it so.
 925                 startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 926                 break;
 927         }
 928
 929         // Add the file to the list of recent files.  This doesn't currently work, but maybe it will someday.
 930         MediaScannerConnection.scanFile(this, new String[] {exportFileString}, new String[] {"application/x-sqlite3"}, null);
 931     }
 932
 933     private void importSettings() {
 934         // Get a handle for the views.
 935         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 936         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 937
 938         // Instantiate the import export database helper.
 939         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 940
 941         // Get the import file.
 942         File importFile = new File(fileNameEditText.getText().toString());
 943
 944         // Initialize the import status string
 945         String importStatus = "";
 946
 947         // Import according to the encryption type.
 948         switch (encryptionSpinner.getSelectedItemPosition()) {
 949             case NO_ENCRYPTION:
 950                 // Import the unencrypted file.
 951                 importStatus = importExportDatabaseHelper.importUnencrypted(importFile, this);
 952                 break;
 953
 954             case PASSWORD_ENCRYPTION:
 955                 // Use a private temporary import location.
 956                 File temporaryUnencryptedImportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 957
 958                 try {
 959                     // Create an encrypted import file input stream.
 960                     FileInputStream encryptedImportFileInputStream = new FileInputStream(importFile);
 961
 962                     // Delete the temporary import file if it exists.
 963                     if (temporaryUnencryptedImportFile.exists()) {
 964                         //noinspection ResultOfMethodCallIgnored
 965                         temporaryUnencryptedImportFile.delete();
 966                     }
 967
 968                     // Create an unencrypted import file output stream.
 969                     FileOutputStream unencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 970
 971                     // Get a handle for the encryption password EditText.
 972                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 973
 974                     // Get the encryption password.
 975                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 976
 977                     // Get the salt from the beginning of the import file.
 978                     byte[] saltByteArray = new byte[32];
 979                     //noinspection ResultOfMethodCallIgnored
 980                     encryptedImportFileInputStream.read(saltByteArray);
 981
 982                     // Get the initialization vector from the import file.
 983                     byte[] initializationVector = new byte[12];
 984                     //noinspection ResultOfMethodCallIgnored
 985                     encryptedImportFileInputStream.read(initializationVector);
 986
 987                     // Convert the encryption password to a byte array.
 988                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 989
 990                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 991                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 992                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 993                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 994
 995                     // Get a SHA-512 message digest.
 996                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 997
 998                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 999                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
1000
1001                     // Truncate the encryption password byte array to 256 bits (32 bytes).
1002                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
1003
1004                     // Create an AES secret key from the encryption password byte array.
1005                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
1006
1007                     // 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.
1008                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
1009
1010                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
1011                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
1012
1013                     // Initialize the cipher.
1014                     cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
1015
1016                     // Create a cipher input stream.
1017                     CipherInputStream cipherInputStream = new CipherInputStream(encryptedImportFileInputStream, cipher);
1018
1019                     // 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.
1020                     int numberOfBytesRead;
1021                     byte[] decryptedBytes = new byte[16];
1022
1023                     // 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.
1024                     while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
1025                         // Write the data to the unencrypted import file output stream.
1026                         unencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
1027                     }
1028
1029                     // Close the streams.
1030                     unencryptedImportFileOutputStream.flush();
1031                     unencryptedImportFileOutputStream.close();
1032                     cipherInputStream.close();
1033                     encryptedImportFileInputStream.close();
1034
1035                     // Wipe the encryption data from memory.
1036                     //noinspection UnusedAssignment
1037                     encryptionPasswordString = "";
1038                     Arrays.fill(saltByteArray, (byte) 0);
1039                     Arrays.fill(initializationVector, (byte) 0);
1040                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
1041                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
1042                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
1043                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
1044                     Arrays.fill(decryptedBytes, (byte) 0);
1045
1046                     // Import the unencrypted database from the private location.
1047                     importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFile, this);
1048
1049                     // Delete the temporary unencrypted import file.
1050                     //noinspection ResultOfMethodCallIgnored
1051                     temporaryUnencryptedImportFile.delete();
1052                 } catch (Exception exception) {
1053                     importStatus = exception.toString();
1054                 }
1055                 break;
1056
1057             case OPENPGP_ENCRYPTION:
1058                 try {
1059                     // Create an decryption intent for OpenKeychain.
1060                     Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
1061
1062                     // Include the URI to be decrypted.
1063                     openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), importFile));
1064
1065                     // Allow OpenKeychain to read the file URI.
1066                     openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
1067
1068                     // Send the intent to the OpenKeychain package.
1069                     openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
1070
1071                     // Make it so.
1072                     startActivity(openKeychainDecryptIntent);
1073                 } catch (IllegalArgumentException exception) {  // The file import location is not valid.
1074                     // Display a snack bar with the import error.
1075                     Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + exception.toString(), Snackbar.LENGTH_INDEFINITE).show();
1076                 }
1077                 break;
1078         }
1079
1080         // Respond to the import disposition.
1081         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {  // The import was successful.
1082             // Create an intent to restart Privacy Browser.
1083             Intent restartIntent = getParentActivityIntent();
1084
1085             // Assert that the intent is not null to remove the lint error below.
1086             assert restartIntent != null;
1087
1088             // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
1089             restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
1090
1091             // Create a restart handler.
1092             Handler restartHandler = new Handler();
1093
1094             // Create a restart runnable.
1095             Runnable restartRunnable =  () -> {
1096                 // Restart Privacy Browser.
1097                 startActivity(restartIntent);
1098
1099                 // Kill this instance of Privacy Browser.  Otherwise, the app exhibits sporadic behavior after the restart.
1100                 System.exit(0);
1101             };
1102
1103             // Restart Privacy Browser after 150 milliseconds to allow enough time for the preferences to be saved.
1104             restartHandler.postDelayed(restartRunnable, 150);
1105
1106         } else if (!(encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION)){  // The import was not successful.
1107             // Display a snack bar with the import error.
1108             Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
1109         }
1110     }
1111 }