Secure AI Chat System (End-To-End Encryption + AI Moderation)

Privacy protection and online safety have become critical challenges in modern messaging platforms, as users increasingly rely on digital communication while facing risks related to data surveillance, message interception, and toxic online behavior. This paper presents the design and implementation of a secure AI-enabled chat system that integrates end-to-end encryption with intelligent content moderation. The proposed system employs AES-256 encryption for securing message content and RSA-based key exchange to ensure confidential communication between users. To maintain a safe conversational environment without compromising privacy, an AI-based moderation module analyses messages on the client side prior to encryption, enabling the detection of toxic, abusive, and spam content. The system is implemented using a web-based frontend built with HTML, CSS, and JavaScript, and a FastAPI backend with WebSocket-based real-time communication. Encryption and moderation are performed on the client side to preserve privacy while ensuring safety. Experimental results demonstrate secure message transmission with no data leakage during testing, and effective moderation performance observed during controlled experiments. The results indicate that strong privacy guarantees and effective content moderation can coexist within a single messaging platform.