End-to-End Encrypted iOS Chat with Apple’s CryptoKit

Building a secure chat app requires implementing end-to-end encryption to ensure user privacy, a feature already standard in major apps like WhatsApp and Telegram. This educational guide demonstrates how to achieve basic end-to-end encryption in an iOS chat application using Apple's CryptoKit framework and Stream's iOS chat SDK. Through examples, it explains the generation of private and public keys, symmetric key derivation via Diffie-Hellman Key Exchange, and the encryption and decryption of messages using AES.GCM. Additionally, the guide covers integrating these methods into a chat app with Stream's SDK and emphasizes the importance of consulting security professionals for a more robust implementation. The tutorial, intended for educational purposes, warns against creating custom encryption protocols without expert guidance and provides a GitHub link for the complete project.