If your source is just a faceless worker who happened to overhear something about their boss, then all they need from you is a burner phone, an email address on a public server, and GPG keys—all of which you can give out the public halves of.
But then how does that prove anything? I can give you an email address and phone number of someone who will tell you anything I want.
But then how does that prove anything? I can give you an email address and phone number of someone who will tell you anything I want.