From The Open Whisper Systems team.
Ranked in these QuestionsQuestion Ranking
Pro Truly open and secure, comes from the Open Whisper Systems Team
Backed by people nut about privacy, including
- Edward Snowden, Whistleblower and privacy advocate
- Laura Poitras, Oscar winning filmmaker and journalist
- Bruce Schneier, internationally renowned security technologist
- Matt Green, Cryptographer, Johns Hopkins University
Pro Encrypted voice calling
Unlike many other apps, signal provides not only text messaging but also live encrypted voice calling.
Pro Free as in both free beer and freedom, not as in "The customer is the product"
Pay Nothing - The development team is supported by community donations and grants. There are no advertisements, and it doesn't cost anything to use.
Con Requires phone number to register
Con Centralized architecture
Signal's server architecture has been partially decentralized since December 2013, when it was announced that the messaging protocol that is used in Signal had successfully been integrated into the Android-based open-source operating system CyanogenMod. As of CyanogenMod 11.0, the client logic is contained in a system app called WhisperPush. According to Open Whisper Systems, "the Cyanogen team runs their own Signal messaging server for WhisperPush clients, which federates with Open Whisper Systems' Signal server, so that both clients can exchange messages with each-other seamlessly".
The WhisperPush source code is available under the GPLv3 license. In January 2016, however, the CyanogenMod team announced that they will be discontinuing WhisperPush on February 1, and recommended that its users switch to Signal. After this, Signal's server architecture will be entirely centralized.
Con Code being used in Whatsapp and other parties undermines trust
It's unlikely FB would add encryption it does not have access to.