After reading this thread I had the question on whether it is possible to verify you have certain information without revealing who you are to others.
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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.
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