Signal is an open-source, encrypted messaging service

• Overview: Signal provides secure instant messaging, voice calls, and video calls. Users can send texts, voice notes, images, videos, and files. All communications are end-to-end encrypted.

• History: It evolved from earlier apps like TextSecure and RedPhone, developed by Whisper Systems. Signal was officially launched in 2014 and has since grown significantly.

• Technology: Signal employs a centralized computing architecture and utilizes the Signal Protocol for its encryption. It is cross-platform, supporting Android, iOS, and desktop systems.

• Privacy Features: It includes features like disappearing messages, user-configurable usernames for added privacy, and face-blurring in photos.

• Development: Signal is developed by Signal Technology Foundation and Signal Messenger LLC. The foundation was launched in 2018 with significant funding from WhatsApp co-founder Brian Acton.

• Reception: It has been praised for its security and privacy features and is widely used globally, particularly by activists, journalists, and privacy-conscious users.