Secure Messaging is a new innovation for confidential story-sharing and source protection, underpinning the Guardian’s commitment to investigative journalism. The Guardian has published the open source code for this important tech to enable adoption by other media organisations.
Not my specialty, but signals end to end encryption is akin to sealing a letter. Nobody but the sender and the recipient can open that letter.
But you still gotta send it through the mail. That’s the network traffic analysis that can be used.
Here’s an example of why that could be bad.