The need for secure and private communication has grown significantly in recent years due to increasing cyber threats and privacy concerns. Existing messaging platforms like WhatsApp, Telegram, and Facebook Messenger offer varying levels of security and functionality but often lack critical features such as real-time spam link detection, anti-screenshot measures, or comprehensive encryption across all services. This project aims to develop Lockbox, a secure messaging application designed to address these gaps. Lockbox focuses on providing end-to-end encryption by default, advanced spam link detection, voice note transcription, and anti-screenshot functionality. The app also includes secure group chats, encrypted file sharing, and user-friendly cross-platform compatibility. The development of Lockbox has achieved significant progress in defining its requirements, analyzing existing solutions, and designing a secure, privacy-first architecture. Early results demonstrate the potential of Lockbox to enhance user privacy while delivering an intuitive and feature-rich messaging experience.