Keys and encryption (PalisadoesFoundation#2027)

* add crypto package and password encryption

* add doc for Encryptor class

* merge with develop

* add key generation

* write docs and suppress some warnings

* fix formatting of lib/views/pre_auth_screens/login.dart

lib/apptheme.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 // import 'package:flutter_screenutil/flutter_screenutil.dart';

lib/router.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_good_doc_comments
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:talawa/constants/routing_constants.dart';

lib/utils/encryptor.dart

@@ -1,5 +1,12 @@
 import 'dart:convert';
+import 'dart:typed_data';
+
 import 'package:crypto/crypto.dart';
+import 'package:hive/hive.dart';
+import 'package:pointycastle/asymmetric/oaep.dart';
+import 'package:pointycastle/asymmetric/rsa.dart';
+import 'package:pointycastle/pointycastle.dart';
+import 'package:pointycastle/random/fortuna_random.dart';
 
 /// Handles all of the encryption tasks in the codebase.
 class Encryptor {
@@ -22,4 +29,122 @@ class Encryptor {
     if (!shouldEncrypt) return data;
     return sha256.convert(utf8.encode(data)).toString();
   }
+
+  /// Generates RSA Key Pairs (Public/Private).
+  ///
+  /// Should be called only during app's first initialization,
+  /// and any future usage should be done by getting the keys
+  /// from the local storage.
+  ///
+  /// **params**:
+  ///   None
+  ///
+  /// **returns**:
+  /// * `AsymmetricKeyPair<PublicKey, PrivateKey>`: The generated
+  /// public and private keys.
+  AsymmetricKeyPair<PublicKey, PrivateKey> generateRSAKeyPair() {
+    final keyGen = RSAKeyGeneratorParameters(BigInt.parse('65537'), 2048, 64);
+    final secureRandom = FortunaRandom();
+    final random = SecureRandom('Fortuna')
+      ..seed(secureRandom as CipherParameters);
+    final keyGenParams = ParametersWithRandom(keyGen, random);
+
+    final keyGenerator = KeyGenerator('RSA');
+    keyGenerator.init(keyGenParams);
+
+    return keyGenerator.generateKeyPair();
+  }
+
+  /// Saves the generated key pair to local storage.
+  ///
+  /// Any future usage of the keys must be initiated from here.
+  ///
+  /// **params**:
+  /// * `keyPair`: [AsymmetricKeyPair] to save.
+  ///
+  /// **returns**:
+  /// * `Future<void>`: None
+  Future<void> saveKeyPair(
+    AsymmetricKeyPair<PublicKey, PrivateKey> keyPair,
+  ) async {
+    // TODO: Implement secure storage here
+
+    await Hive.openBox<AsymmetricKeyPair<PublicKey, PrivateKey>>('user_keys');
+    final keysBox = await Hive.openBox('user_keys');
+
+    keysBox.put('key_pair', keyPair);
+  }
+
+  /// Loads secret keys from the Hive db.
+  ///
+  /// **params**:
+  ///   None
+  ///
+  /// **returns**:
+  /// * `Future<AsymmetricKeyPair<PublicKey, PrivateKey>>`: The public and
+  /// private key pair
+  Future<AsymmetricKeyPair<PublicKey, PrivateKey>> loadKeyPair() async {
+    await Hive.openBox<AsymmetricKeyPair<PublicKey, PrivateKey>>('user_keys');
+    final keysBox = await Hive.openBox('user_keys');
+
+    return (await keysBox.get('key_pair'))
+        as AsymmetricKeyPair<PublicKey, PrivateKey>;
+  }
+
+  /// Encrypts the given string data with Recipient's Public Key.
+  ///
+  /// **params**:
+  /// * `data`: The string to encrypt
+  /// * `recipientPublicKey`: Key to be used to encrypt. Recipient's public
+  /// key in our case.
+  ///
+  /// **returns**:
+  /// * `String`: Encrypted string
+  String assymetricEncryptString(String data, RSAPublicKey recipientPublicKey) {
+    final cipher = OAEPEncoding(RSAEngine())
+      ..init(true, PublicKeyParameter<RSAPublicKey>(recipientPublicKey));
+
+    final encryptedBytes = cipher.process(Uint8List.fromList(data.codeUnits));
+    return base64Encode(encryptedBytes);
+  }
+
+  /// Encrypts the given string data with user's Private Key.
+  ///
+  /// **params**:
+  /// * `data`: The string to decrypt
+  /// * `privateKey`: Key to be used to decrypt. User's private key in our case.
+  ///
+  /// **returns**:
+  /// * `String`: Decrypted string
+  String assymetricDecryptString(String data, RSAPrivateKey privateKey) {
+    final cipher = OAEPEncoding(RSAEngine())
+      ..init(false, PrivateKeyParameter<RSAPrivateKey>(privateKey));
+
+    final decryptedBytes = cipher.process(base64Decode(data));
+    return String.fromCharCodes(decryptedBytes);
+  }
+
+  /// Helper function to decrypt the message.
+  ///
+  /// Internally uses the [loadKeyPair] function to get private key and
+  /// [assymetricDecryptString] to decrypt the given message.
+  ///
+  /// **params**:
+  /// * `message`: Message object containing a field named [encryptedMessage]
+  /// which is supposed to contained user's message in encrypted format.
+  ///
+  /// **returns**:
+  /// * `Future<void>`: None
+  /// TODO: Use this somewhere
+  Future<void> receiveMessage(Map<String, dynamic> message) async {
+    final privateKey = (await loadKeyPair()).privateKey;
+
+    final encryptedMessage = message['encryptedMessage'] as String;
+    final decryptedMessage = assymetricDecryptString(
+      encryptedMessage,
+      privateKey as RSAPrivateKey,
+    );
+
+    print('Decrypted Message: $decryptedMessage');
+  }
 }

lib/view_model/access_request_view_model.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc
 import 'package:flutter/cupertino.dart';
 import 'package:graphql_flutter/graphql_flutter.dart';
 import 'package:talawa/constants/routing_constants.dart';

lib/view_model/pre_auth_view_models/select_organization_view_model.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_good_doc_comments, talawa_api_doc
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:graphql_flutter/graphql_flutter.dart';

lib/views/after_auth_screens/feed/organization_feed.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:talawa/view_model/after_auth_view_models/feed_view_models/organization_feed_view_model.dart';
 import 'package:talawa/view_model/main_screen_view_model.dart';

lib/views/after_auth_screens/join_org_after_auth/access_request_screen.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_good_doc_comments, talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:talawa/apptheme.dart';
 import 'package:talawa/models/organization/org_info.dart';

lib/views/after_auth_screens/join_org_after_auth/join_organisation_after_auth.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc, talawa_good_doc_comments
 import 'package:flutter/material.dart';
 import 'package:qr_code_scanner/qr_code_scanner.dart';
 import 'package:talawa/enums/enums.dart';

lib/views/after_auth_screens/profile/profile_page.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc
 import 'package:contained_tab_bar_view/contained_tab_bar_view.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_braintree/flutter_braintree.dart';

lib/views/pre_auth_screens/login.dart

@@ -10,6 +10,7 @@ import 'package:talawa/widgets/raised_round_edge_button.dart';
 import 'package:talawa/widgets/rich_text.dart';
 
 /// This is the login widget.
+///
 /// There are two input fiels. The first one takes in the email and
 /// the second one takes in the password of the user.
 /// There is also a "Forgot Password" text button, which directs to

lib/widgets/custom_avatar.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_good_doc_comments, talawa_api_doc
 import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_cache_manager/flutter_cache_manager.dart';

lib/widgets/custom_list_tile.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_good_doc_comments, talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:talawa/enums/enums.dart';
 import 'package:talawa/models/options/options.dart';

lib/widgets/post_container.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:visibility_detector/visibility_detector.dart';
 

lib/widgets/post_detailed_page.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_good_doc_comments, talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:talawa/utils/app_localization.dart';
 

lib/widgets/post_list_widget.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:talawa/models/post/post_model.dart';
 import 'package:talawa/widgets/post_widget.dart';

lib/widgets/post_widget.dart

@@ -1,3 +1,4 @@
+// ignore_for_file: talawa_api_doc
 import 'package:flutter/material.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:talawa/models/post/post_model.dart';

pubspec.lock

@@ -5,10 +5,10 @@ packages:
     dependency: transitive
     description:
       name: _fe_analyzer_shared
-      sha256: "405666cd3cf0ee0a48d21ec67e65406aad2c726d9fa58840d3375e7bdcd32a07"
+      sha256: ae92f5d747aee634b87f89d9946000c2de774be1d6ac3e58268224348cd0101a
       url: "https://pub.dev"
     source: hosted
-    version: "60.0.0"
+    version: "61.0.0"
   _flutterfire_internals:
     dependency: transitive
     description:
@@ -21,10 +21,10 @@ packages:
     dependency: transitive
     description:
       name: analyzer
-      sha256: "1952250bd005bacb895a01bf1b4dc00e3ba1c526cf47dca54dfe24979c65f5b3"
+      sha256: ea3d8652bda62982addfd92fdc2d0214e5f82e43325104990d4f4c4a2a313562
       url: "https://pub.dev"
     source: hosted
-    version: "5.12.0"
+    version: "5.13.0"
   analyzer_plugin:
     dependency: transitive
     description:
@@ -266,7 +266,7 @@ packages:
     source: hosted
     version: "0.3.3+4"
   crypto:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: crypto
       sha256: ff625774173754681d66daaf4a448684fb04b78f902da9cb3d308c19cc5e8bab
@@ -301,26 +301,26 @@ packages:
     dependency: "direct dev"
     description:
       name: custom_lint
-      sha256: "3ce36c04d30c60cde295588c6185b3f9800e6c18f6670a7ffdb3d5eab39bb942"
+      sha256: "837821e4619c167fd5a547b03bb2fc6be7e65b800ec75528848429705c31ceba"
       url: "https://pub.dev"
     source: hosted
-    version: "0.4.0"
+    version: "0.5.3"
   custom_lint_builder:
     dependency: transitive
     description:
       name: custom_lint_builder
-      sha256: "73d09c9848e9f6d5c3e0a1809eac841a8d7ea123d0849feefa040e1ad60b6d06"
+      sha256: "3537d50202568994a6f42b1f2953aed6292fc5ecf83e45237af73f64aff2be72"
       url: "https://pub.dev"
     source: hosted
-    version: "0.4.0"
+    version: "0.5.3"
   custom_lint_core:
     dependency: transitive
     description:
       name: custom_lint_core
-      sha256: "9170d9db2daf774aa2251a3bc98e4ba903c7702ab07aa438bc83bd3c9a0de57f"
+      sha256: "3bdebdd52a42b4d6e5be9cd833ad1ecfbbc23e1020ca537060e54085497aea9c"
       url: "https://pub.dev"
     source: hosted
-    version: "0.4.0"
+    version: "0.5.3"
   dart_style:
     dependency: transitive
     description:
@@ -1261,6 +1261,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.6"
+  pointycastle:
+    dependency: "direct main"
+    description:
+      name: pointycastle
+      sha256: "7c1e5f0d23c9016c5bbd8b1473d0d3fb3fc851b876046039509e18e0c7485f2c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.7.3"
   pool:
     dependency: transitive
     description:
@@ -1813,10 +1821,10 @@ packages:
     dependency: transitive
     description:
       name: watcher
-      sha256: "6a7f46926b01ce81bfc339da6a7f20afbe7733eff9846f6d6a5466aa4c6667c0"
+      sha256: "3d2ad6751b3c16cf07c7fca317a1413b3f26530319181b37e3b9039b84fc01d8"
       url: "https://pub.dev"
     source: hosted
-    version: "1.0.2"
+    version: "1.1.0"
   web:
     dependency: transitive
     description:

pubspec.yaml

@@ -25,6 +25,7 @@ dependencies:
   connectivity_plus: ^4.0.2
   contained_tab_bar_view: ^0.8.0
 
+  crypto: ^3.0.3
   cupertino_icons: ^1.0.3
   currency_picker: ^2.0.16
 
@@ -58,14 +59,15 @@ dependencies:
   http: ^1.1.0
   image_cropper: ^5.0.0
 
-  intl: ^0.18.0
   image_picker: ^1.0.4
+  intl: ^0.18.0
   json_annotation: ^4.7.0
   mockito: ^5.4.2
   network_image_mock: ^2.1.1
   path_provider: ^2.1.1
   permission_handler: ^11.0.0
   plugin_platform_interface: ^2.1.6
+  pointycastle: ^3.7.3
   provider: ^6.0.3
   qr_code_scanner: ^1.0.0
   qr_flutter: 4.0.0