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What makes WhatsApp and Signal secure for messaging?
How does end-to-end encryption work in chat applications?
What is the role of the Web Cryptography API in secure messaging?
How can I build a secure chat app using Flutter and DhiWise?
Why is end-to-end encryption important in real-time chat apps?
Chat applications such as WhatsApp and Signal are undoubtedly the most convenient and secure way to communicate with your friends, family, and colleagues. According to Statista, as of April 2024, two billion users accessed WhatsApp Messenger monthly. And Signal had around 20 million app installations at the end of last year.
But do you know what makes these apps so secure for private messaging and media sharing? Let's take a look at why these end-to-end encrypted chat application platforms are dominating other similar app platforms.
WhatsApp and Signal are end-to-end-encrypted messaging apps, which means the platform can not access private messages or media, or store them on their server without encryption. And this is the most important feature of the real-time chat application.
In this article, we will cover:
A real-time chat application sends and receives data instantly over the network among multiple clients. This enables users to connect immediately with anyone and exchange messages and media files like images, audio, and videos.
Real-time chat applications mostly use client-server architecture for data transfer. The software displays messages in real-time to one or more people in a channel or group. However, how those messages are processed, manipulated, and maintained differs from platform to platform.
Having end-to-end encrypted chat applications ensures users' data security, as users are more likely to exchange their personal information through chats like financial details, passwords, user IDs, etc.
So, let's take a look at what end-to-end encryption means and how it works.
End-to-end encryption is the mechanism where the messages are secured in a way so that no third party can access or tamper them. Only the sender and receiver can access those messages. The messages are stored in encrypted form on the server running a chat application.
The only way to access these messages is by decrypting them through signing with the known public key and the corresponding private key pair.
So how do the encryption and decryption of messages take place using public and private keys?
Each user in the chat app has their own public and private key pair. The Public key (distributed publicly) is used to encrypt the sender's message, while the receiver can only decrypt the sender’s message with the matching private key.
For implementing end-to-end encryption in the chat application you can use cryptography API that helps you to perform basic cryptographic operations in the chat application.
The Web Cryptography API is the JavaScript API that can be used to perform basic cryptographic operations such as hashing, encryption, and decryption. It is a low-level interface recommended by the World Wide Web Consortium.
For using the Web Cryptographic API in your Flutter application use the webcrypto 0.5.3 package. It provides a cross-platform implementation of the Web Cryptography APIs for Flutter.
Outside the browser, this package features a native implementation embedding BoringSSL using dart:ffi . And when used inside the web browser this package wraps the window.crypto APIs and provides the same Dart API as the native implementation. In this way, it provides the same API on multiple platforms such as the Web, Android, and iOS.
To build the Flutter app using DhiWise, first Sign up with DhiWise using a Google or GitHub account and then follow the steps below.
To start building a mobile application you need to select the app development technology and the Figma design platform.
DhiWise allows its users to directly use their Figma design inside the DhiWise platform moreover if the users don't have their design ready DhiWise provides them with ready-to-use app templates .
To access their Figma design they just need a Figma design file URL and then the design components are automatically fetched into the DhiWise platform.
Create Flutter Chat App
While the platform fetches the Figma file, you can configure the Flutter app by selecting the desired state management library (from BLoC, Provider, GetX, and Riverpod) or build the app without state management. Also, you can select the desired Flutter SDK version.
Code Configuration
If you have your Figma design ready, use the Figma file URL to fetch Figma components in the app design. You can select a number of screens that you want to customize inside DhiWise to generate the Flutter application code.
Select Screens
So this is how the platform identifies chat application components once the screens are selected.
Auto- Identified Components
The platform empowers developers to customize UI components and styling at the code level. Just select the component, and it will be highlighted in the code editor. The code editor provides suggestions similar to any other IDE, so you can customize the code in the way you want.
To make things faster and easier, the platform enables you to synchronize the Figma design changes for a single screen or all screens. Its component detection algorithm auto-detects the interactions in the design prototype like navigation and actions.
In fact, it allows you to set up lifecycle methods, and navigation and add arguments with just a click.
Configure app screens
As the chat application starts users should be able to connect with the real-time stream chat. For that developers need to store the user’s public key as extra data. Anyone with the user's public key can encrypt a message using it and the same can be decrypted using the corresponding private key. That's the reason why private keys should be saved securely.
To generate a key add webcrypto 0.5.3 package to your pubspec.yaml file under dependencies.
1 2 3 4 5dependencies: flutter: sdk: flutter cupertino_icons: ^1.0.2 webcrypto: ^0.5.3
Next, write a function that generates a key pair using the ECDH algorithm and the P-256 elliptic curve. Also, you will need to create widgets for the users and channels in the chat application.
Finally, to encrypt and decrypt messages one needs to use the Crypto Key generated using the key pair used by the two communicating users.
In case you want to create your own API, or upload Postman collections of files, DhiWise Flutter builder lets you do that with its API integration feature.
Read our help doc to know more about API integration in the Flutter application with DhiWise.
Once your UI customization is done for all app screens, you can quickly preview your application and share the preview with team members. Next to generate the code click build app and the platform will start generating your application code.
Preview and Generate App Code
Once the final code is generated it can be downloaded or synchronized with the GitHub and GitLab repositories.
Download Chat App Code
In this article, we've explored the essentials of building an end-to-end encrypted chat application, from understanding secure messaging principles to implementing encryption with the Web Cryptography API in Flutter. DhiWise makes the entire app development journey smoother by offering a user-friendly, feature-rich platform that accelerates development without sacrificing customization or security. If you're searching for an efficient, intuitive solution to create a secure Flutter app, DhiWise Flutter Builder has you covered. Ready to build your next Flutter app with DhiWise? 🚀
