This is a code snippet from a flutter application that demonstrate how to encrypt and decrypt string data. here is a link to appetize.io [https://appetize.io/app/b_ddw6xwd525iqb4zdfkr4ifxg3u] to checkfunctionality.

crypting_widget.dart

import 'package:flutter/material.dart';
import 'package:encrypt/encrypt.dart' as encrypt;

// Created a stateful widget for encryption and decryption
class CryptingWidget extends StatefulWidget {
  const CryptingWidget({super.key});
  @override
  CryptingWidgetState createState() => CryptingWidgetState();
}

class CryptingWidgetState extends State<CryptingWidget> {
  // Intoduced the encryption key and initialization vector-IV
  final key = encrypt.Key.fromLength(32);
  final iv = encrypt.IV.fromLength(16);

  // this line here creates an encrypter instance using AES algorithm
  final encrypter = encrypt.Encrypter(encrypt.AES(encrypt.Key.fromLength(32)));

  // Variables to store encrypted and decrypted values
  String encryptedText = '';
  String decryptedText = '';

  // this method is used to encrypt the input text
  void _encrypt(String text) {
    final encrypted = encrypter.encrypt(text, iv: iv);
    setState(() {
      encryptedText = encrypted.base64;
    });
  }

  // this method is used to decrypt the encrypted text
  void _decrypt(String text) {
    final decrypted = encrypter.decrypt64(text, iv: iv);
    setState(() {
      decryptedText = decrypted;
    });
  }

  // UI of the widget is built here
  @override
  Widget build(BuildContext context) {
    return Padding(
      // Add padding around the widget
      padding: const EdgeInsets.all(50),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          // Text field for entering text to encrypt
          TextFormField(
            onChanged: (text) {
              _encrypt(text);
            },
            decoration: InputDecoration(
                prefixIcon: Icon(Icons.enhanced_encryption),
                labelText: 'Enter text to encrypt'),
          ),
          SizedBox(height: 20),
          // Display the encrypted text
          Text(
            'Encrypted: $encryptedText',
            style: TextStyle(color: Colors.deepPurple),
          ),
          SizedBox(height: 20),
          // Button to decrypt encrpted text
          ElevatedButton(
            onPressed: () {
              _decrypt(encryptedText);
            },
            child: Text('Decrypt'),
          ),
          SizedBox(height: 20),
          // Display the decrypted text
          Text('Decrypted: $decryptedText',
              style: TextStyle(color: Colors.blueAccent)),
        ],
      ),
    );
  }
}

home.dart

import 'package:flutter/material.dart';
import '../theme/theme.dart';
import '../widgets/crypting_widget.dart';

class App extends StatelessWidget {
  const App({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      themeMode: ThemeMode.system,
      theme: EAppTheme.lightTheme,
      darkTheme: EAppTheme.darkTheme,
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.deepPurple,
          title: Text('Crypting App',
            style: TextStyle(
              color: Colors.white,
            ),
          ),
        ),
        body: Center(
          child: CryptingWidget(),
        ),
      ),
    );
  }
}

image.md

UI

instructions for useage.md

Usage

Enter the text you want to encrypt in the first text field. The encrypted text will be displayed below the text field. Press the "Decrypt" button to decrypt the encrypted text. The decrypted text will be displayed below the button.

main.dart

import 'package:flutter/material.dart';

import 'screen/home.dart';

void main() {
  runApp(App());
}