From Wired:

A key part of what makes Signal the leading encrypted messaging app is its effort to minimize the amount of data or metadata each message leaves behind. The messages themselves are fully encrypted as they move across Signal’s infrastructure, and the service doesn’t store logs of information like who sends messages to each other, or when. On Monday, the nonprofit that develops Signal announced a new initiative to take those protections even further. Now, it hopes to encrypt even information about which users are messaging each other on the platform.