A Step-by-Step Guide to Building an Encrypted Messaging App

No matter whether you own a large business or have remote workers on your team – effective communication is vital. However, some chat apps put your data at risk, and this is where the need for secure messaging solutions comes in. As users have become more aware of the importance of securing their personal and professional communications, encrypted messaging apps have become more popular. Although there are many other ways to secure your data, end-to-end encryption is now a standard security feature in messaging apps.


Before we proceed with the secure chat app development, let’s define End-to-End Encrypted Messaging first:

What Exactly Is End-To-End Encrypted Messaging?

Encrypted messaging, commonly referred to as “secure messaging,” provides end-to-end encryption for user-to-user conversations. Encrypted messaging makes it impossible for others to read your text conversations. However, several White-label video chat APIs provide end-to-end encryption for phone calls made and files sent via the apps. As the data is encoded using encryption, only the particular recipient can read it.


An encrypted message uses an algorithm, which directly converts information so that it is impossible to read by anyone who lacks the necessary decryption tool.


Email communications comprising sensitive or confidential information must be encrypted. Encryption gives you an extra layer of security if you’re dealing with sensitive client information or simply want to ensure that your private conversations remain private.

Reasons Why Choose a Secure Instant Messenger

Generally, a message sent to a friend is routed through a server. Without encryption, this message will get transmitted in plain text, and anyone with access can read it. Encryption converts the message from plain text to ciphertext – encrypted with a key – transfer and then back (decrypted) on your friend’s device using a paired key.


Whether it’s a White-label chat API or an iOS White-label chat SDK, most instant messaging apps now use end-to-end encryption. It prevents anyone except you and your friend from reading the messages. 


End-to-end encryption has flaws, despite its apparent reliability. For instance:


Failure to recover message history if a user changes or loses their device and there is no server to store the chat history.


Vulnerability to man-in-the-middle (MITM) attacks, in which skilled MITM hackers can hijack conversations, hack public keys, and even deliver forged messages while being recognized as legitimate recipients by the system.


Signal developers have added a Double Ratchet Algorithm to their protocol’s end-to-end encryption to combat MITM attacks. This technique creates session keys in addition to the public and private keys when users install the app.  Session keys are generated for each message sent and self-destruct when the session ends. Even if MITM attackers obtain the key for a single session, they will be unable to decrypt all messages.


Moreover, the Double Ratchet Algorithm is not the only thing that distinguishes the Signal app from other secure messaging apps.

How to Build an Encrypted Chat App?

Have you ever wondered how to create Encrypted Messaging Apps for iOS or Encrypted Messaging Apps for Android? If so, we’ve got you covered. 


Let’s discuss the different stages of Chat App Development here:


  • Discovery


Before you begin the Customizable Chat App Development process, you must first assess the needs of your target audience.


  • Design


At this stage, you’ll learn about the basic concepts of your secure chat app through wireframes and black-and-white prototypes.


  • Development


The duration of chat app development may vary depending on the complexity of the app’s features and the number of platforms for which you choose to build your app.


  • Testing


This stage is for troubleshooting and honing your custom instant chat app to perfection. The quality assurance specialists will analyze feedback from early users, run multiple tests to find and fix bugs, and make recommendations on how to improve the app.

Must-Have Features of an Encrypted Messaging App

The following are some of the must-have features of the Secure Chat App:


  • End-to-End Encryption


With end-to-end encryption, only the sender and the recipient of a message have the “key” to decrypt the chat message.


  • Permission Levels


A secure online messaging app will always need access to your device. Different permission levels must be included in the app.


  • Secure Source Code


The source code for a secure instant messaging application is secure. Thus, confirm that the app has received the most recent security certifications.


  • Data Storage Restrictions


The lesser data stored on devices, the better it is in terms of security. It limits data exposure, especially for documents or media shared among employees.


  • Option to Delete Messages


Unintentional messages can be sent by anyone. Everyone, not just the admin, should have the option to delete unwanted messages in a chat app.

How Much Would it Cost to Create an Encrypted Chat Application?

The cost of developing an encrypted chat app highly depends on the following factors:


  • Set of features
  • UI/UX Design
  • App Developer
  • App Testing
  • Team Size


And considerably more.

The Challenges of Developing Secure Messaging Applications

  • Every time a media file is sent, chat crashes.


Such flaws can happen because, first, media files are generally large in size, putting a heavy load on the system during processing, transferring, and ciphering; second, end-to-end encryption of these files implies a rejection of the encrypted chat server, indicating that all processes will take place on the client side.


Solution: Analyze the algorithm that parallelizes encryption, decryption, and key stream creation in your secure messenger to streamline data transmission, coding, and decoding.


  • The app’s performance is far from excellent.


Due to the heavily loaded client side, app speed generally slows down as well.


Solution. In this case, it’s vital to run load tests to identify the most overloaded app spots and then restore order in the client’s internal database by reorganizing its structure specifically.

Summing Up

We hope this blog post has given you deeper insight into the key aspects of developing secure chat applications. Consider using Customized Chat SDK for iOS or Customizable Chat APIs if you need to develop an encrypted chat app for your business. If you search the market, you will likely come across a plethora of chat app APIs and SDKs like MirrorFly, Sendbird and Getstream. And, MirrorFly has been my personal favorite for years. Why wait? Start building your secure chat app today.