Signal Messenger is a free, open-source messaging app designed to provide secure, private communication through end-to-end encryption. It allows users to send text messages, voice calls, video calls, and media files, ensuring that only the intended recipients can access the content. While Signal is widely recognized for its strong privacy protections, it has also been misused by cybercriminals to deliver malicious files and coordinate attacks, taking advantage of its encrypted channels to evade detection.