Facebook Messenger

Although Facebook Messenger may not be the first software that springs to mind when it comes to encrypted messaging, the mobile versions of the service provide end-to-end encrypted communication options in the form of Secret Conversations. Secret Conversations, which uses the same encryption mechanism as Signal, needs users to opt-in. It enables people to send and receive encrypted text, photographs, and stickers to and from a single mobile device, with the ability to sending and receiving time-limited self-destructing messages alike Snapchat.

Messenger recently added the option for end-to-end encryption of one-to-one voice and video conversations, and the company has stated that it is testing end-to-end encryption of group chats, calls, and video chats. However, Facebook Messenger is still vulnerable to screen-grabs, and the opt-in and single-device restrictions might be a problem. It's also Facebook.

Detailed information:

Self-Destructing Messages: Yes
Data Stored: Encrypted Data

Website: https://www.messenger.com