>I plan to allow users to share their non-anonymized information in an encrypted peer-to-peer fashion with each other if they want to. This answers the question like, “Oh, somebody earns twice as much as me… And has the same job title… Who is that?”

Couldn't you find a bunch of people who are in that job title in your org? I'm sure with some detective work you could connect the dots on individuals you care to track down, depending on the size of the company.