Signal

Overview

Signal is widely regarded as the most secure messaging application available. Developed by the Signal Foundation, a non-profit, it uses the Signal Protocol for end-to-end encryption, which has been independently audited and is also used by WhatsApp and Google Messages. The critical difference is that Signal collects almost no metadata: it does not know who you message, when, or how often.

Signal supports text messaging, voice and video calls, group chats, file sharing, and disappearing messages. All communications are encrypted by default with no option to disable encryption.

Privacy and Security

Signal's Sealed Sender feature hides even the sender's identity from Signal's servers. The application stores minimal data: when subpoenaed by the US government, Signal could only provide the date an account was created and the date it last connected. No message content, contacts, groups, or profile information was available. This has been verified through court documents and transparency reports.

Who Should Use It

Signal is the right choice for anyone who values private communication. It is straightforward enough for non-technical users while providing security that satisfies the most demanding threat models. The only significant limitation is the requirement for a phone number to register, though usernames for contact discovery are being developed to address this.