Is it possible to use zero knowledge proofs to verify journalism sources?

Only if it is information that would be available to many people.

And for every bit of information shared, you have to think of the number of people who have access to the information you are sharing and all of the previous information you shared.

If someone is aware there is a leak they might generate different versions of the same information to narrow it down.

If you’re a whistleblower, it also assumes you didn’t make a big stink about the topic.

I doubt that would work since the nature of the information often already limits the number of people who might have access to it severely.

You could use zkp to verify the identity of someone.

What "certain information" do you wish to verify?

Whenever I state Reuters as my source about a topic I totally made up, all the other newspapers who also want to be the first to comment about a topic also state Reuters as their source.

Source: Reuters