How to build a chat app for secure communication?

Communication is the lifeline of an organization. As vast amounts of data are to be regularly stored and exchanged—protecting them from unauthorized access is paramount. 

Worryingly, data breaches have been on the rise in the last decade.  

In 2024, for example, 6.9 billion records were breached in 2,741 publicly disclosed incidents in the USA. 

On top of it, data breaches are a costly affair. IBM’s Cost of a Data Breach Report 2024 shows that the global average cost of a data breach in 2024 was 4.88 million USD. 

Therefore, organizations must proactively defend their internal and external communications. One way to ensure this is to build a chat app that is secure, collaboration-friendly, and reliable. 

In this blog post, we have covered the important components and step-by-step processes you need if you want to build a chat app.

‍Understanding the basics of secure communication

To put it simply, secure communication prevents unauthorized access to information shared between two entities. It increases the customer’s trust and reputation of the brand. 

Incorporating the security features ensures compliance with region and industry-specific laws like GDPR, HIPAA, FINRA, and so on. 

To note, non-compliance with these laws involves hefty fines. For instance, the violation of HIPAA incurs penalties ranging from $137 to $68,928 per violation. 

So, what constitutes secure communication? Let’s look at its basic components:

End-to-end encryption

End-to-end encryption (E2EE) is a crucial component of secure communication. It employs complex algorithms to transform readable data into unreadable ciphertext. In online chat rooms, it protects data at rest and in transit.

No metadata storage

In 2023, there was a 160% increase in attempts to steal sensitive information like passwords and keys from cloud services by accessing metadata, which has the sender and recipient names and their respective IP addresses. 

So, automatically deleting the metadata from chat platforms reduces the security risk involved. 

Secure authentication

Secure authentication methods like multi-factor authentication and role-based access prevent unauthorized access to sensitive data. Microsoft reports that multi-factor authentication can block 99.9% of automated cyberattacks. 

Secure communication protocols

Finally, communication protocols like HTTPS and TLS encrypt data in transmission to protect interception from unauthorized third parties.  

‍How to build a chat app for secure communication?

To build a chat app for establishing secure communication, follow the steps:

Choose the right technology stack

Investing in the right technology stack helps achieve a foolproof and functional chat application. The common frameworks and languages include:

Front-end frameworks

• React Native supports cross-platform development using React and JavaScript. 
• Flutter, Google’s UI toolkit, supports natively compiled mobile, web, and desktop applications from a single codebase. 
• Swift supports iOS and Kotlin works for Android apps. 

Backend languages

• Node.js is a JavaScript with a non-blocking I/O model capable of managing multiple connections. So, it is appropriate for large-scale organizations with high traffic. 
• Python has a simple syntax and can be used with WebSockets, Django, or Flask for efficient backend services. 

Real-time communication

• WebSockets support instant message delivery. 
• Socket.io is a JavaScript library that supports bi-directional communication. 

A secure technology stack helps protect sensitive data from cyberattacks and breaches. Using secure libraries like Socket.IO or WebSockets along with encryption protocols like OpenSSL or TLS drives secure message transmission.  

‍Implement end-to-end encryption 

End-to-end encryption in the chat engine ensures that messages can be accessed only by the intended recipient. It prevents third parties from accessing the data transmitted and increases customers’ trust in the organization. 

Encryption algorithms:

Selecting the right encryption algorithm is crucial when you build a chat app. Popular ones include:

• AES (Advanced Encryption Standard) uses the same key for encryption and decryption. It is quick and can handle large amounts of data. 
• RSA (Rivest-Shamir-Adleman) uses large, asymmetric keys. So, it is secure, yet slow for large-scale transmissions. 
• Elliptic Curve Cryptography (ECC) has smaller keys than RSA, making it reliable for real-time exchanges. 

Steps to implementing end-to-end encryption in the chat app

• Step 1: First, you must choose appropriate libraries. The chat initiator generates a key and the public key is then shared with another user. 
• Step 2: A secure connection between the sender and recipient is established using secure protocols like SSL or TLS. 
• Step 3: The message is then encrypted using the recipient’s public key. This ensures that the recipient can decrypt the message with the private key. 
• Step 4: The encrypted message is transmitted across secure communication channels like WebSockets. 
• Step 5: Upon reception, the message can be decrypted with the private keys, and the keys are deleted, right after the exchange.

Authentication and authorization

User authentication checks the user's credentials to ensure that only authorized personnel can access the application. It helps implement role-based access and ensures that users act within the permitted fringes.

Common authentication protocols include:

• OAuth is a token-based authentication that allows third parties to use specific parts of the user information. This works if you prefer to allow users to log in to the chat app using their social media or Gmail credentials. 
• JSON Web Tokens are secure standards for sharing information between client and server. It is appropriate for API authentication and server-to-server authorization. 
• Single Sign-On (SSO) allows users associated with an enterprise to access authorized applications using the same credentials. It is quick and easy for the admin to have control over the access. 

Steps to implementing user authentication in the chat app

• Step 1: Design a form to collect user details along with their credentials. Validate the credential with the one stored in the database. Communicate the results of the validation to the client. 
• Step 2: Define user roles and implement authentication at different checkpoints to protect a specific route.
•  Step 3: Use secure protocols like HTTPS to secure the communication.