Added Feature: Password Entropy

authpass/lib/ui/screens/create_file.dart

@@ -4,6 +4,7 @@ import 'package:authpass/ui/widgets/password_input_field.dart';
 import 'package:authpass/ui/widgets/primary_button.dart';
 import 'package:authpass/utils/dialog_utils.dart';
 import 'package:authpass/utils/extension_methods.dart';
+import 'package:authpass/utils/password_entropy.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
@@ -30,13 +31,15 @@ class CreateFile extends StatefulWidget {
 
 class _CreateFileState extends State<CreateFile> with FutureTaskStateMixin {
   static final _zxcvbn = Zxcvbn();
+  static final _calculatePasswordEntropy=PasswordEntropy();
 
   final GlobalKey<FormState> _formKey = GlobalKey();
   final TextEditingController _databaseName = TextEditingController();
   final TextEditingController _password = TextEditingController();
   final FocusNode _passwordFocus = FocusNode();
 
   Result _strength;
+  String _passwordEntropy;
 
   @override
   void didChangeDependencies() {
@@ -96,9 +99,12 @@ class _CreateFileState extends State<CreateFile> with FutureTaskStateMixin {
                     setState(() {
                       if (value.isEmpty) {
                         _strength = null;
+                        _passwordEntropy = null;
                       } else {
                         _strength =
                             _zxcvbn.evaluate(value, userInputs: userInput);
+                        _passwordEntropy =
+                            _calculatePasswordEntropy.passwordEntropy(value);
                       }
                     });
                   },
@@ -112,6 +118,8 @@ class _CreateFileState extends State<CreateFile> with FutureTaskStateMixin {
                 const SizedBox(height: 8),
                 PasswordStrengthDisplay(strength: _strength),
                 const SizedBox(height: 8),
+                _passwordEntropy!=null?Text('Entrophy: $_passwordEntropy'):Container(),
+                const SizedBox(height: 8),
                 Text(
                   'The master password is used to securely encrypt your password database. Make sure to remember it, it can not be restored.',
                   style: Theme.of(context).textTheme.caption,

authpass/lib/utils/password_entropy.dart

@@ -0,0 +1,18 @@
+import 'dart:math';
+
+//   Entropy(H) = L * log2(N)
+//   L = Length of password
+//   N = Number of special characters
+
+class PasswordEntropy {
+  String passwordEntropy(String value) {
+    double logBase(num x, num base) => log(x) / log(base);
+
+    final n =
+        RegExp(r'[!"#$%&()*+,-./:;<=>?@[\]^_`{|}~]').allMatches(value).length;
+
+    final l = value.length;
+
+    return (l * logBase(n, 2)).toStringAsFixed(2);
+  }
+}

authpass/pubspec.lock

@@ -754,7 +754,7 @@ packages:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.4"
+    version: "1.3.0-nullsafety.3"
   mime:
     dependency: "direct main"
     description:
@@ -1178,7 +1178,7 @@ packages:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.2"
+    version: "1.10.0-nullsafety.1"
   stream_channel:
     dependency: transitive
     description:
@@ -1485,5 +1485,5 @@ packages:
     source: hosted
     version: "0.0.1"
 sdks:
-  dart: ">=2.10.0-110 <=2.11.0-213.0.dev"
+  dart: ">=2.10.0-110 <2.11.0"
   flutter: ">=1.18.0-6.0.pre <2.0.0"