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

   1 /*
   2  * Copyright © 2018 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.app.DialogFragment;
  25 import android.content.Intent;
  26 import android.content.pm.PackageManager;
  27 import android.net.Uri;
  28 import android.os.Build;
  29 import android.os.Bundle;
  30 import android.os.Environment;
  31 import android.provider.DocumentsContract;
  32 import android.support.annotation.NonNull;
  33 import android.support.design.widget.Snackbar;
  34 import android.support.design.widget.TextInputLayout;
  35 import android.support.v4.app.ActivityCompat;
  36 import android.support.v4.content.ContextCompat;
  37 import android.support.v7.app.ActionBar;
  38 import android.support.v7.app.AppCompatActivity;
  39 import android.support.v7.widget.Toolbar;
  40 import android.text.Editable;
  41 import android.text.TextWatcher;
  42 import android.view.View;
  43 import android.view.WindowManager;
  44 import android.widget.AdapterView;
  45 import android.widget.ArrayAdapter;
  46 import android.widget.Button;
  47 import android.widget.EditText;
  48 import android.widget.Spinner;
  49 import android.widget.TextView;
  50
  51 import com.stoutner.privacybrowser.R;
  52 import com.stoutner.privacybrowser.dialogs.ImportExportStoragePermissionDialog;
  53 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  54
  55 import java.io.File;
  56 import java.io.FileInputStream;
  57 import java.io.FileOutputStream;
  58 import java.security.MessageDigest;
  59 import java.security.SecureRandom;
  60 import java.util.Arrays;
  61
  62 import javax.crypto.Cipher;
  63 import javax.crypto.CipherInputStream;
  64 import javax.crypto.CipherOutputStream;
  65 import javax.crypto.spec.GCMParameterSpec;
  66 import javax.crypto.spec.SecretKeySpec;
  67
  68 public class ImportExportActivity extends AppCompatActivity implements ImportExportStoragePermissionDialog.ImportExportStoragePermissionDialogListener {
  69     // Create the encryption constants.
  70     private final int NO_ENCRYPTION = 0;
  71     private final int PASSWORD_ENCRYPTION = 1;
  72     private final int GPG_ENCRYPTION = 2;
  73
  74     // Create the action constants.
  75     private final int IMPORT = 0;
  76     private final int EXPORT = 1;
  77
  78     @Override
  79     public void onCreate(Bundle savedInstanceState) {
  80         // Disable screenshots if not allowed.
  81         if (!MainWebViewActivity.allowScreenshots) {
  82             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
  83         }
  84
  85         // Set the activity theme.
  86         if (MainWebViewActivity.darkTheme) {
  87             setTheme(R.style.PrivacyBrowserDark_SecondaryActivity);
  88         } else {
  89             setTheme(R.style.PrivacyBrowserLight_SecondaryActivity);
  90         }
  91
  92         // Run the default commands.
  93         super.onCreate(savedInstanceState);
  94
  95         // Set the content view.
  96         setContentView(R.layout.import_export_coordinatorlayout);
  97
  98         // Use the `SupportActionBar` from `android.support.v7.app.ActionBar` until the minimum API is >= 21.
  99         Toolbar importExportAppBar = findViewById(R.id.import_export_toolbar);
 100         setSupportActionBar(importExportAppBar);
 101
 102         // Display the home arrow on the support action bar.
 103         ActionBar appBar = getSupportActionBar();
 104         assert appBar != null;// This assert removes the incorrect warning in Android Studio on the following line that `appBar` might be null.
 105         appBar.setDisplayHomeAsUpEnabled(true);
 106
 107         // Get handles for the views that need to be modified.
 108         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 109         TextInputLayout passwordEncryptionTextInputLayout = findViewById(R.id.password_encryption_textinputlayout);
 110         EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 111         Spinner importExportSpinner = findViewById(R.id.import_export_spinner);
 112         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 113         Button importExportButton = findViewById(R.id.import_export_button);
 114         TextView storagePermissionTextView = findViewById(R.id.import_export_storage_permission_textview);
 115
 116         // Create array adapters for the spinners.
 117         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 118         ArrayAdapter<CharSequence> importExportArrayAdapter = ArrayAdapter.createFromResource(this, R.array.import_export_spinner, R.layout.spinner_item);
 119
 120         // Set the drop down view resource on the spinners.
 121         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 122         importExportArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 123
 124         // Set the array adapters for the spinners.
 125         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 126         importExportSpinner.setAdapter(importExportArrayAdapter);
 127
 128         // Initially hide the encryption layout items.
 129         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 130
 131         // Create strings for the default file paths.
 132         String defaultFilePath;
 133         String defaultPasswordEncryptionFilePath;
 134         String defaultGpgEncryptionFilePath;
 135
 136         // Set the default file paths according to the storage permission status.
 137         if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 138             // Set the default file paths to use the external public directory.
 139             defaultFilePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + getString(R.string.privacy_browser_settings);
 140             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 141             defaultGpgEncryptionFilePath = defaultFilePath + ".gpg";
 142         } else {  // The storage permission has not been granted.
 143             // Set the default file paths to use the external private directory.
 144             defaultFilePath = getApplicationContext().getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS) + "/" + getString(R.string.privacy_browser_settings);
 145             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 146             defaultGpgEncryptionFilePath = defaultFilePath + ".gpg";
 147         }
 148
 149         // Set the default file path.
 150         fileNameEditText.setText(defaultFilePath);
 151
 152         // Display the encryption information when the spinner changes.
 153         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 154             @Override
 155             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 156                 switch (position) {
 157                     case NO_ENCRYPTION:
 158                         // Hide the encryption layout items.
 159                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 160
 161                         // Reset the default file path.
 162                         fileNameEditText.setText(defaultFilePath);
 163
 164                         // Enable the import/export button if a file name exists.
 165                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 166                         break;
 167
 168                     case PASSWORD_ENCRYPTION:
 169                         // Show the password encryption layout items.
 170                         passwordEncryptionTextInputLayout.setVisibility(View.VISIBLE);
 171
 172                         // Update the default file path.
 173                         fileNameEditText.setText(defaultPasswordEncryptionFilePath);
 174
 175                         // Enable the import/export button if a file name and password exists.
 176                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 177                         break;
 178
 179                     case GPG_ENCRYPTION:
 180                         // Hide the password encryption layout items.
 181                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 182
 183                         // Update the default file path.
 184                         fileNameEditText.setText(defaultGpgEncryptionFilePath);
 185                         break;
 186                 }
 187             }
 188
 189             @Override
 190             public void onNothingSelected(AdapterView<?> parent) {
 191
 192             }
 193         });
 194
 195         // Update the import/export button when the spinner changes.
 196         importExportSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 197             @Override
 198             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 199                 switch (position) {
 200                     case IMPORT:
 201                         importExportButton.setText(R.string.import_button);
 202                         break;
 203
 204                     case EXPORT:
 205                         importExportButton.setText(R.string.export);
 206                         break;
 207                 }
 208             }
 209
 210             @Override
 211             public void onNothingSelected(AdapterView<?> parent) {
 212
 213             }
 214         });
 215
 216         // Update the status of the import/export button when the password changes.
 217         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 218             @Override
 219             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 220                 // Do nothing.
 221             }
 222
 223             @Override
 224             public void onTextChanged(CharSequence s, int start, int before, int count) {
 225                 // Do nothing.
 226             }
 227
 228             @Override
 229             public void afterTextChanged(Editable s) {
 230                 // Enable the import/export button if a file name and password exists.
 231                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 232             }
 233         });
 234
 235         // Update the status of the import/export button when the file name EditText changes.
 236         fileNameEditText.addTextChangedListener(new TextWatcher() {
 237             @Override
 238             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 239                 // Do nothing.
 240             }
 241
 242             @Override
 243             public void onTextChanged(CharSequence s, int start, int before, int count) {
 244                 // Do nothing.
 245             }
 246
 247             @Override
 248             public void afterTextChanged(Editable s) {
 249                 // Adjust the export button according to the encryption spinner position.
 250                 switch (encryptionSpinner.getSelectedItemPosition()) {
 251                     case NO_ENCRYPTION:
 252                         // Enable the import/export button if a file name exists.
 253                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 254                         break;
 255
 256                     case PASSWORD_ENCRYPTION:
 257                         // Enable the import/export button if a file name and password exists.
 258                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 259                         break;
 260
 261                     case GPG_ENCRYPTION:
 262                         break;
 263                 }
 264             }
 265         });
 266
 267         // Hide the storage permissions TextView on API < 23 as permissions on older devices are automatically granted.
 268         if (Build.VERSION.SDK_INT < 23) {
 269             storagePermissionTextView.setVisibility(View.GONE);
 270         }
 271     }
 272
 273     public void browse(View view) {
 274         // Get a handle for the import/export spinner.
 275         Spinner importExportSpinner = findViewById(R.id.import_export_spinner);
 276
 277         // Check to see if import or export is selected.
 278         if (importExportSpinner.getSelectedItemPosition() == IMPORT) {  // Import is selected.
 279             // Create the file picker intent.
 280             Intent importIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 281
 282             // Set the intent MIME type to include all files.
 283             importIntent.setType("*/*");
 284
 285             // Set the initial directory if API >= 26.
 286             if (Build.VERSION.SDK_INT >= 26) {
 287                 importIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 288             }
 289
 290             // Specify that a file that can be opened is requested.
 291             importIntent.addCategory(Intent.CATEGORY_OPENABLE);
 292
 293             // Launch the file picker.
 294             startActivityForResult(importIntent, 0);
 295         } else {  // Export is selected
 296             // Create the file picker intent.
 297             Intent exportIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 298
 299             // Set the intent MIME type to include all files.
 300             exportIntent.setType("*/*");
 301
 302             // Set the initial export file name.
 303             exportIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.privacy_browser_settings));
 304
 305             // Set the initial directory if API >= 26.
 306             if (Build.VERSION.SDK_INT >= 26) {
 307                 exportIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 308             }
 309
 310             // Specify that a file that can be opened is requested.
 311             exportIntent.addCategory(Intent.CATEGORY_OPENABLE);
 312
 313             // Launch the file picker.
 314             startActivityForResult(exportIntent, 0);
 315         }
 316     }
 317
 318     public void importExport(View view) {
 319         // Get a handle for the import/export spinner.
 320         Spinner importExportSpinner = findViewById(R.id.import_export_spinner);
 321
 322         // Check to see if the storage permission has been granted.
 323         if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // Storage permission granted.
 324             // Check to see if import or export is selected.
 325             if (importExportSpinner.getSelectedItemPosition() == IMPORT) {  // Import is selected.
 326                 // Import the settings.
 327                 importSettings();
 328             } else {  // Export is selected.
 329                 // Export the settings.
 330                 exportSettings();
 331             }
 332         } else {  // Storage permission not granted.
 333             // Get a handle for the file name EditText.
 334             EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 335
 336             // Get the file name string.
 337             String fileNameString = fileNameEditText.getText().toString();
 338
 339             // Get the external private directory `File`.
 340             File externalPrivateDirectoryFile = getApplicationContext().getExternalFilesDir(null);
 341
 342             // Remove the lint error below that the `File` might be null.
 343             assert externalPrivateDirectoryFile != null;
 344
 345             // Get the external private directory string.
 346             String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
 347
 348             // Check to see if the file path is in the external private directory.
 349             if (fileNameString.startsWith(externalPrivateDirectory)) {  // The file path is in the external private directory.
 350                 // Check to see if import or export is selected.
 351                 if (importExportSpinner.getSelectedItemPosition() == IMPORT) {  // Import is selected.
 352                     // Import the settings.
 353                     importSettings();
 354                 } else {  // Export is selected.
 355                     // Export the settings.
 356                     exportSettings();
 357                 }
 358             } else {  // The file path is in a public directory.
 359                 // Check if the user has previously denied the storage permission.
 360                 if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
 361                     // Instantiate the storage permission alert dialog.
 362                     DialogFragment importExportStoragePermissionDialogFragment = new ImportExportStoragePermissionDialog();
 363
 364                     // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
 365                     importExportStoragePermissionDialogFragment.show(getFragmentManager(), getString(R.string.storage_permission));
 366                 } else {  // Show the permission request directly.
 367                     // Request the storage permission.  The export will be run when it finishes.
 368                     ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 369                 }
 370             }
 371         }
 372     }
 373
 374     @Override
 375     public void onCloseImportExportStoragePermissionDialog() {
 376         // Request the write external storage permission.  The import/export will be run when it finishes.
 377         ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 378     }
 379
 380     @Override
 381     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
 382         // Get a handle for the import/export spinner.
 383         Spinner importExportSpinner = findViewById(R.id.import_export_spinner);
 384
 385         // Check to see if import or export is selected.
 386         if (importExportSpinner.getSelectedItemPosition() == IMPORT) {  // Import is selected.
 387             // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 388             if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 389                 // Import the settings.
 390                 importSettings();
 391             } else {  // The storage permission was not granted.
 392                 // Display an error snackbar.
 393                 Snackbar.make(importExportSpinner, getString(R.string.cannot_import), Snackbar.LENGTH_LONG).show();
 394             }
 395         } else {  // Export is selected.
 396             // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 397             if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 398                 // Export the settings.
 399                 exportSettings();
 400             } else {  // The storage permission was not granted.
 401                 // Display an error snackbar.
 402                 Snackbar.make(importExportSpinner, getString(R.string.cannot_export), Snackbar.LENGTH_LONG).show();
 403             }
 404         }
 405     }
 406
 407     @Override
 408     public void onActivityResult(int requestCode, int resultCode, Intent data) {
 409         // Don't do anything if the user pressed back from the file picker.
 410         if (resultCode == Activity.RESULT_OK) {
 411             // Get a handle for the file name EditText.
 412             EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 413
 414             // Get the file name URI.
 415             Uri fileNameUri = data.getData();
 416
 417             // Remove the lint warning that the file name URI might be null.
 418             assert fileNameUri != null;
 419
 420             // Get the raw file name path.
 421             String rawFileNamePath = fileNameUri.getPath();
 422
 423             // Remove the warning that the file name path might be null.
 424             assert rawFileNamePath != null;
 425
 426             // Check to see if the file name Path includes a valid storage location.
 427             if (rawFileNamePath.contains(":")) {  // The path is valid.
 428                 // Split the path into the initial content uri and the final path information.
 429                 String fileNameContentPath = rawFileNamePath.substring(0, rawFileNamePath.indexOf(":"));
 430                 String fileNameFinalPath = rawFileNamePath.substring(rawFileNamePath.indexOf(":") + 1);
 431
 432                 // Create the file name path string.
 433                 String fileNamePath;
 434
 435                 // Construct the file name path.
 436                 switch (fileNameContentPath) {
 437                     // The documents home has a special content path.
 438                     case "/document/home":
 439                         fileNamePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + fileNameFinalPath;
 440                         break;
 441
 442                     // Everything else for the primary user should be in `/document/primary`.
 443                     case "/document/primary":
 444                         fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 445                         break;
 446
 447                     // Just in case, catch everything else and place it in the external storage directory.
 448                     default:
 449                         fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 450                         break;
 451                 }
 452
 453                 // Set the file name path as the text of the file name EditText.
 454                 fileNameEditText.setText(fileNamePath);
 455             } else {  // The path is invalid.
 456                 Snackbar.make(fileNameEditText, rawFileNamePath + " + " + getString(R.string.invalid_location), Snackbar.LENGTH_INDEFINITE).show();
 457             }
 458         }
 459     }
 460
 461     private void exportSettings() {
 462         // Get a handle for the views.
 463         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 464         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 465
 466         // Instantiate the import export database helper.
 467         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 468
 469         // Get the export file.
 470         File exportFile = new File(fileNameEditText.getText().toString());
 471
 472         // Initialize the export status string.
 473         String exportStatus = "";
 474
 475         // Export according to the encryption type.
 476         switch (encryptionSpinner.getSelectedItemPosition()) {
 477             case NO_ENCRYPTION:
 478                 // Export the unencrypted file.
 479                 exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, this);
 480                 break;
 481
 482             case PASSWORD_ENCRYPTION:
 483                 // Use a private temporary export location.
 484                 File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/export.temp");
 485
 486                 // Create an unencrypted export in the private location.
 487                 exportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 488
 489                 try {
 490                     // Create an unencrypted export file input stream.
 491                     FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 492
 493                     // Delete the encrypted export file if it exists.
 494                     if (exportFile.exists()) {
 495                         //noinspection ResultOfMethodCallIgnored
 496                         exportFile.delete();
 497                     }
 498
 499                     // Create an encrypted export file output stream.
 500                     FileOutputStream encryptedExportFileOutputStream = new FileOutputStream(exportFile);
 501
 502                     // Get a handle for the encryption password EditText.
 503                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 504
 505                     // Get the encryption password.
 506                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 507
 508                     // Initialize a secure random number generator.
 509                     SecureRandom secureRandom = new SecureRandom();
 510
 511                     // Get a 256 bit (32 byte) random salt.
 512                     byte[] saltByteArray = new byte[32];
 513                     secureRandom.nextBytes(saltByteArray);
 514
 515                     // Convert the encryption password to a byte array.
 516                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes("UTF-8");
 517
 518                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 519                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 520                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 521                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 522
 523                     // Get a SHA-512 message digest.
 524                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 525
 526                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 527                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 528
 529                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 530                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 531
 532                     // Create an AES secret key from the encryption password byte array.
 533                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 534
 535                     // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 536                     byte[] initializationVector = new byte[12];
 537                     secureRandom.nextBytes(initializationVector);
 538
 539                     // 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.
 540                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 541
 542                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 543                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 544
 545                     // Initialize the cipher.
 546                     cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 547
 548                     // Add the salt and the initialization vector to the export file.
 549                     encryptedExportFileOutputStream.write(saltByteArray);
 550                     encryptedExportFileOutputStream.write(initializationVector);
 551
 552                     // Create a cipher output stream.
 553                     CipherOutputStream cipherOutputStream = new CipherOutputStream(encryptedExportFileOutputStream, cipher);
 554
 555                     // 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.
 556                     int numberOfBytesRead;
 557                     byte[] encryptedBytes = new byte[16];
 558
 559                     // 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.
 560                     while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 561                         // Write the data to the cipher output stream.
 562                         cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 563                     }
 564
 565                     // Close the streams.
 566                     cipherOutputStream.flush();
 567                     cipherOutputStream.close();
 568                     encryptedExportFileOutputStream.close();
 569                     unencryptedExportFileInputStream.close();
 570
 571                     // Wipe the encryption data from memory.
 572                     //noinspection UnusedAssignment
 573                     encryptionPasswordString = "";
 574                     Arrays.fill(saltByteArray, (byte) 0);
 575                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 576                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 577                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 578                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 579                     Arrays.fill(initializationVector, (byte) 0);
 580                     Arrays.fill(encryptedBytes, (byte) 0);
 581
 582                     // Delete the temporary unencrypted export file.
 583                     //noinspection ResultOfMethodCallIgnored
 584                     temporaryUnencryptedExportFile.delete();
 585                 } catch (Exception exception) {
 586                     exportStatus = exception.toString();
 587                 }
 588                 break;
 589
 590             case GPG_ENCRYPTION:
 591
 592                 break;
 593         }
 594
 595         // Show a disposition snackbar.
 596         if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 597             Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 598         } else {
 599             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 600         }
 601     }
 602
 603     private void importSettings() {
 604         // Get a handle for the views.
 605         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 606         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 607
 608         // Instantiate the import export database helper.
 609         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 610
 611         // Get the import file.
 612         File importFile = new File(fileNameEditText.getText().toString());
 613
 614         // Initialize the import status string
 615         String importStatus = "";
 616
 617         // Import according to the encryption type.
 618         switch (encryptionSpinner.getSelectedItemPosition()) {
 619             case NO_ENCRYPTION:
 620                 // Import the unencrypted file.
 621                 importStatus = importExportDatabaseHelper.importUnencrypted(importFile, this);
 622                 break;
 623
 624             case PASSWORD_ENCRYPTION:
 625                 // Use a private temporary import location.
 626                 File temporaryUnencryptedImportFile = new File(getApplicationContext().getCacheDir() + "/import.temp");
 627
 628                 try {
 629                     // Create an encrypted import file input stream.
 630                     FileInputStream encryptedImportFileInputStream = new FileInputStream(importFile);
 631
 632                     // Delete the temporary import file if it exists.
 633                     if (temporaryUnencryptedImportFile.exists()) {
 634                         //noinspection ResultOfMethodCallIgnored
 635                         temporaryUnencryptedImportFile.delete();
 636                     }
 637
 638                     // Create an unencrypted import file output stream.
 639                     FileOutputStream unencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 640
 641                     // Get a handle for the encryption password EditText.
 642                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 643
 644                     // Get the encryption password.
 645                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 646
 647                     // Get the salt from the beginning of the import file.
 648                     byte[] saltByteArray = new byte[32];
 649                     //noinspection ResultOfMethodCallIgnored
 650                     encryptedImportFileInputStream.read(saltByteArray);
 651
 652                     // Get the initialization vector from the import file.
 653                     byte[] initializationVector = new byte[12];
 654                     //noinspection ResultOfMethodCallIgnored
 655                     encryptedImportFileInputStream.read(initializationVector);
 656
 657                     // Convert the encryption password to a byte array.
 658                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes("UTF-8");
 659
 660                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 661                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 662                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 663                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 664
 665                     // Get a SHA-512 message digest.
 666                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 667
 668                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 669                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 670
 671                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 672                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 673
 674                     // Create an AES secret key from the encryption password byte array.
 675                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 676
 677                     // 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.
 678                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 679
 680                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 681                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 682
 683                     // Initialize the cipher.
 684                     cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 685
 686                     // Create a cipher input stream.
 687                     CipherInputStream cipherInputStream = new CipherInputStream(encryptedImportFileInputStream, cipher);
 688
 689                     // 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.
 690                     int numberOfBytesRead;
 691                     byte[] decryptedBytes = new byte[16];
 692
 693                     // 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.
 694                     while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 695                         // Write the data to the unencrypted import file output stream.
 696                         unencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 697                     }
 698
 699                     // Close the streams.
 700                     unencryptedImportFileOutputStream.flush();
 701                     unencryptedImportFileOutputStream.close();
 702                     cipherInputStream.close();
 703                     encryptedImportFileInputStream.close();
 704
 705                     // Wipe the encryption data from memory.
 706                     //noinspection UnusedAssignment
 707                     encryptionPasswordString = "";
 708                     Arrays.fill(saltByteArray, (byte) 0);
 709                     Arrays.fill(initializationVector, (byte) 0);
 710                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 711                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 712                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 713                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 714                     Arrays.fill(decryptedBytes, (byte) 0);
 715
 716                     // Import the unencrypted database from the private location.
 717                     importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFile, this);
 718
 719                     // Delete the temporary unencrypted import file.
 720                     //noinspection ResultOfMethodCallIgnored
 721                     temporaryUnencryptedImportFile.delete();
 722                 } catch (Exception exception) {
 723                     importStatus = exception.toString();
 724                 }
 725                 break;
 726
 727             case GPG_ENCRYPTION:
 728
 729                 break;
 730         }
 731
 732         // Respond to the import disposition.
 733         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {  // The import was successful.
 734             // Create an intent to restart Privacy Browser.
 735             Intent restartIntent = getParentActivityIntent();
 736
 737             // Assert that the intent is not null to remove the lint error below.
 738             assert restartIntent != null;
 739
 740             // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 741             restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 742
 743             // Make it so.
 744             startActivity(restartIntent);
 745         } else {  // The import was not successful.
 746             // Display a snack bar with the import error.
 747             Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 748         }
 749     }
 750 }